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Smart search ranks by meaning as well as keywords (one row per story, last 45 days).
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N-able N-central Pre-Auth RCE Flaw Exploited in the Wild
CISA added CVE-2026-86218 (CVSS 10.0), a pre-auth RCE in N-able N-central, to KEV after N-able confirmed in-the-wild exploitation; patch by September 11.
CISA added CVE-2026-86218, a maximum-severity static code injection flaw enabling pre-authentication remote code execution in N-able N-central, to its Known Exploited Vulnerabilities catalog with a September 11, 2026 deadline for federal agencies. The flaw is fixed in N-central 2026.3 Hotfix 4 (released September 5), and N-able told customers it has been observed being exploited in the wild. Separately, Huntress is investigating the compromise of a fully patched customer N-central environment on September 4 and cannot yet confirm which flaw was used, while Rapid7-disclosed CVE-2026-86206 and CVE-2026-86207 can be chained by an unauthenticated attacker to create a rogue System Administrator account.
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PaperCut Zero-Day: Active Exploitation and Pre-Auth RCE
PaperCut NG/MF hit by a pre-auth RCE zero-day under active exploitation; Huntress reproduced the chain and urged immediate patching.
Huntress reports active exploitation of a zero-day in PaperCut NG and PaperCut MF, and says it reproduced a pre-authentication remote code execution chain. The flaw allows unauthenticated attackers to execute code on exposed PaperCut servers. Huntress published urgent patching, exposure-reduction, and detection guidance. No CVE identifier was provided in the announcement.
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You’re Back In The Room (Citrix NetScaler Pre-Auth RCE CVE-2026-8452(?))
watchTowr Labs details a pre-authentication remote code execution flaw, tracked as CVE-2026-8452, in Citrix NetScaler appliances.
watchTowr Labs published technical analysis of a pre-authentication remote code execution vulnerability in Citrix NetScaler, tentatively assigned CVE-2026-8452. The CVE identifier is marked as provisional in the write-up. No confirmation of in-the-wild exploitation is provided in the available text.
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Off Guard: Breaking LiteLLM from authentication bypass to cloud compromise
Wiz found LiteLLM auth bypass (CVE-2026-59822) and post-auth RCE (CVE-2026-59821) chainable to cloud compromise; the bypass is in CISA KEV with in-the-wild exploitation.
Wiz scanned roughly 3,074 internet-facing LiteLLM deployments and found 9.6% accepted the default master key sk-1234 or required no authentication, making post-auth attacks effectively pre-auth. The MCP endpoint accepts any Bearer token and grants a valid session (CVE-2026-59822), confirmed exploited in the wild via honeypots and added to CISA's Known Exploited Vulnerabilities catalog. Custom code guardrails allow post-auth root-level RCE via exec(compile(...)) (CVE-2026-59821), while pass-through endpoints lack URL validation, enabling cloud credential theft in post-auth scenarios. All assigned vulnerabilities have been patched; the research was presented at DEF CON 34.
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WordPress wp2shell Vulnerabilities Exploited in the Wild (CVE-2026 ...
Public exploit code emerged for the WordPress wp2shell pre-auth RCE chain (CVE-2026-63030, CVE-2026-60137); CISA set a July 24 patching deadline.
CVE-2026-63030 (REST API batch-route confusion) chained with CVE-2026-60137 (SQL injection in WP_Query's author__not_in) enables pre-authentication RCE in WordPress core, affecting versions 6.8.0-7.0.1. Multiple researchers published working PoCs on GitHub that extract password hashes, crack admin credentials, and upload malicious plugins. CISA added both CVEs to its KEV catalog with a July 24, 2026 deadline, and WordPress.org enabled forced auto-updates; fixes shipped in 6.8.6, 6.9.5, and 7.0.2.
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CVE-2026-49364: Apache Artemis, Apache ActiveMQ Artemis: Pre-Authentication Cluster Credential Exposure to Discovered Peers
Apache Artemis CVE-2026-49364 exposes cluster credentials to network-adjacent peers discovered before authentication completes.
Apache disclosed a pre-authentication credential exposure issue in Apache Artemis and Apache ActiveMQ Artemis, tracked as CVE-2026-49364. Affected components span artemis-core-client and artemis-server from version 1.0.0 (ActiveMQ Artemis) and 2.50.0 (Artemis) through 2.44.0 and 2.56.0 respectively. An unauthenticated network-adjacent attacker can leverage credentials exposed to discovered cluster peers. Apache rates the issue as important.
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Critical N-able N-central Vulnerability and Active Exploitation
N-able N-central pre-auth RCE zero-day CVE-2026-86218 (CVSS 10.0) is exploited in the wild; on-prem admins must upgrade to 2026.3 HF4.
N-able disclosed a third N-central vulnerability, CVE-2026-86218, a pre-authentication RCE rated CVSS 10.0, and released hotfix 2026.3 HF4 superseding build 2026.3.1.13. Huntress reproduced an exploit chain involving an authentication bypass (CVE-2026-86206/CVE-2026-86207) after a fully patched customer's N-central production server was compromised on September 4. Attackers appended strings like .invalid to account names and probed the /remoteControlAction.do?method=getPierDetails endpoint; Huntress worked with Cloudflare to disable adversary tunnel infrastructure. Hosted N-central instances are already patched; on-prem administrators must upgrade immediately.
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CVE-2026-76186: Apache Airflow Keycloak provider: Keycloak token cookies not bound to Airflow session identity
Apache Airflow Keycloak provider takes authorization tokens from unauthenticated cookies never checked against the signed session identity, enabling cookie substitution.
CVE-2026-76186 affects apache-airflow-providers-keycloak before 0.10.0. From Airflow 3.3, the Keycloak auth manager derives user identity from the signed Airflow session token but reads Keycloak access and refresh tokens used for every authorization decision from separate unauthenticated cookies. It never verifies that the two correspond to the same user, allowing mismatched token cookies to drive authorization decisions. Severity is rated moderate.
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Researchers Use Claude to Port Pre-Auth RCE Exploit From One PLC Model to Another
Forescout used Anthropic's Claude to port a working pre-auth RCE exploit for CVE-2021-31886 between WAGO PLCs, executing ARM shellcode on live hardware.
Forescout Vedere Labs used Claude interactively to port an RCE exploit for CVE-2021-31886, a CVSS 9.8 stack buffer overflow in the Nucleus FTP server's USER command, from a WAGO 750-852 to a WAGO 750-831 PLC, running attacker-supplied ARM shellcode. The final RCE stage cost $535.74 in API usage over 8 hours 32 minutes, and a follow-up attempt to build a C2 implant permanently bricked the device. CERT@VDE lists many Nucleus V1-based WAGO models as vulnerable with no updates available; Siemens plans no Nucleus NET remediation. The work follows a joint NSA/CISA/FBI/DOE/EPA advisory warning of AI-generated exploitation scripts targeting internet-exposed Siemens S7 PLCs.
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[webapps] miniOrange 5.4.3 - Unauthenticated Auth Bypass
A proof-of-concept exploit for an unauthenticated authentication bypass in miniOrange 5.4.3 has been published on Exploit-DB.
Exploit-DB lists a public proof-of-concept exploit for an unauthenticated authentication bypass in miniOrange 5.4.3. The flaw allows attackers to bypass authentication without credentials. No in-the-wild exploitation or CVE identifier is stated in the listing.
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NIS2 compliance: Fixing IAM and access control before the 2026 audit
EU NIS2 enforcement deadlines approach; organizations are urged to prioritize service account inventory, lifecycle offboarding, and phishing-resistant MFA before audits.
EU member states are moving from NIS2 transposition into enforcement, with fines up to 10 million euros or 2% of global turnover for essential entities and personal liability for management bodies. The article argues access management is the fastest high-ROI starting point, estimating 2-4 weeks to enforce fine-grained password policy, vault shared credentials, and deploy phishing-resistant MFA versus 6-12 months for supply chain risk management. It flags three common pre-audit failures: unmanaged service accounts and API keys, dormant accounts from broken offboarding, and SMS OTP instead of phishing-resistant MFA under NIST SP 800-63B. The piece promotes Passwork as a single control plane for credential storage, RBAC, and WebAuthn.
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CVE-2026-86219: Authen::SASL::Perl::DIGEST_MD5 versions before 2.2100 for Perl accept replayed authentication responses via unverified nonce in server_step
Authen::SASL::Perl::DIGEST_MD5 before 2.2100 for Perl accepts replayed DIGEST-MD5 authentication responses via unverified nonce handling (CVE-2026-86219).
CVE-2026-86219 affects Authen::SASL::Perl::DIGEST_MD5 versions before 2.2100 for Perl. The server_step function does not verify the nonce, allowing replayed authentication responses to be accepted in DIGEST-MD5 SASL exchanges. The fix is available in version 2.2100 of the perl-authen-sasl distribution.
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Credentialed Pre-Port Discovery: Don't Probe the Host, Ask it
Rapid7's version 8.58 adds credentialed pre-port discovery, letting scan engines query hosts for listening TCP/UDP ports instead of network probing.
Rapid7 documents credentialed pre-port discovery, available from version 8.58 as an off-by-default per-template option under Asset Discovery. The scan engine authenticates with existing SSH, Scan Assistant, or Windows credentials and receives the host's authoritative list of listening TCP and UDP ports, skipping the network port scan. Hosts without matching credentials silently fall back to network port scanning. Trade-offs include reporting firewall-blocked ports the engine cannot reach, longer scans, and early termination findings caused by repeated connection failures.
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Apple macOS Screen Sharing Flaw Exploited on Internet
Actively exploited CVE-2026-65400 in macOS Screen Sharing grants pre-auth root access; attackers deploy Monero miners on exposed systems.
NCSC-NL reported active exploitation of CVE-2026-65400 (CVSS 9.8), an authentication flaw in macOS Screen Sharing patched on August 6, 2026, with root access gained and a Monero miner planted on internet-exposed systems using port 5900. Related Screen Sharing bugs CVE-2026-43779, CVE-2026-43777, and CVE-2026-43760 were fixed in macOS Tahoe 26.6, and researcher @osxreverser noted a pre-auth flaw fixed alongside them affecting roughly 40,000 exposed hosts. Calif said an AI agent produced working exploits for both pre-auth bugs in four hours, underscoring the shrinking gap between patch release and weaponization.
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CVE-2026-86466: Apache Airflow FAB provider: FAB Authentik provider: id_token issuer/audience not validated
Apache Airflow FAB provider before 3.9.0 skips issuer/audience validation on Authentik id_tokens, allowing tokens minted for other clients to authenticate to Airflow.
CVE-2026-86466 affects apache-airflow-providers-fab before 3.9.0. The Authentik OAuth path in the FAB auth manager does not validate the issuer or audience claims of accepted id_tokens. An attacker holding a token minted by the same Authentik identity provider for a different client application can present it to Airflow and be authenticated. Severity is rated moderate by the reporter.
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New Mirai Variant Targeting Network Security Devices
New Mirai botnet variant exploits nine vulnerabilities in SonicWall, D-Link, Netgear, and other devices, with attacks ongoing at publication.
Unit 42 observed attacks exploiting VisualDoor (SonicWall SSL-VPN), CVE-2020-25506 (D-Link DNS-320), CVE-2020-26919 (Netgear ProSAFE Plus), and other flaws, with infrastructure rotating across at least three IP addresses between February 16 and March 13, 2021. Payloads were updated hours after CVE-2021-27561 and CVE-2021-27562 (Yealink Device Management, unauthenticated root RCE) and later added CVE-2021-22502 (Micro Focus Operation Bridge Reporter) and CVE-2019-19356 (Netis WF2419). Successful exploitation invokes wget to fetch shell scripts that download Mirai binaries compiled for multiple architectures and brute-forcers, and attacks were still ongoing when reported.
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SonicWall Patches Two New Actively Exploited Zero
SonicWall patches two actively exploited SMA 1000 VPN zero-days: CVSS 10.0 pre-auth SSRF CVE-2026-83548 and post-auth command injection CVE-2026-83549, chained for RCE.
SonicWall released hotfixes for two zero-day vulnerabilities in its SMA 1000 VPN appliances, with SonicWall PSIRT confirming active exploitation in the wild. CVE-2026-83548 (CVSS 10.0) is a pre-authentication SSRF in the Appliance Work Place interface allowing unauthenticated unauthorized operations; CVE-2026-83549 (CVSS 7.8) is a post-authentication OS command injection in the Appliance Management Console enabling arbitrary command execution and RCE. The flaws affect models 6210, 7210 and 8200v running 12.4.3-03453 or earlier and 12.5.0-02835 or earlier, fixed in versions 12.4.3-03526 and 12.5.0-02952. This follows a July Volexity report on threat actor UTA0533 chaining two SMA 1000 zero-days to gain root access and deploy the KNUCKLEBALL Python backdoor.
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What Good Identity Hardening Looks Like
Huntress guidance defines mature identity hardening beyond baseline MFA, covering exception cleanup and detecting identity configuration drift before attackers do.
Huntress argues MFA is only a starting point and outlines what mature identity hardening actually looks like in practice. The guidance covers closing MFA exceptions and coverage gaps that create unauthenticated attack paths. It also stresses catching identity configuration drift before attackers can exploit it.
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CVE-2026-81578 + CVE-2026-82078 | PaperCut NG/MF Authentication Bypass and Unsafe Dynamic Class Loading Vulnerabilities
Two chained PaperCut NG/MF flaws, CVE-2026-81578 and CVE-2026-82078, enable pre-auth RCE, with active exploitation confirmed in customer environments.
PaperCut NG/MF is affected by CVE-2026-81578, an improper access control flaw (CVSS 4.0 8.8) allowing unauthenticated configuration changes, and CVE-2026-82078, an unsafe dynamic class loading flaw (CVSS 4.0 9.4) enabling arbitrary Java bytecode execution. Chained, they yield pre-authentication remote code execution on the PaperCut Application Server. PaperCut confirmed active exploitation and customer incidents, and Huntress observed exploitation starting August 26, 2026. Emergency Patch Release 2 is available for NG/MF v24-v26, with IOCs including suspicious pc-app.exe child processes, truncated server.log files, and AnyDesk installs.
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CVE-2026-82435: Apache Storm Worker: Unauthenticated Remote Memory Exhaustion in the Worker Messaging Decoder
Unauthenticated remote memory exhaustion in Apache Storm Worker 3.0.x Netty decoder fixed in 3.1.0, allowing pre-auth denial of service.
CVE-2026-82435 (rated important) affects Apache Storm Worker (org.apache.storm:storm-client) versions 3.0.0 before 3.1.0. The worker's Netty message decoder sits ahead of SASL authentication handlers and processes frames before any authentication occurs. It allocates buffers sized from an attacker-controlled length field, so a single frame from an unauthenticated peer reaching the worker can exhaust memory. Users must upgrade to 3.1.0.
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Rapid7 Analysis: Microsoft SharePoint JWT Token Authentication Bypass (CVE-2026-55040)
Rapid7's analysis of SharePoint auth bypass CVE-2026-55040 includes a PoC for unauthenticated admin-level operations.
Rapid7 and Microsoft disclosed CVE-2026-55040, an authentication bypass in Microsoft SharePoint, on July 14, 2026. The flaw stems from multiple issues in SharePoint's JWT token validation pipeline, allowing a remote unauthenticated attacker to bypass authentication and perform operations as a site user or administrator. Rapid7 has now published a technical analysis and a proof-of-concept script, based on SharePoint Server Subscription Edition.
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PaperCut NG/MF Zero-day Vulnerability Exploited in the Attacks (CVE-2026-82078 & CVE-2026-81578)
PaperCut NG/MF zero-days CVE-2026-82078 and CVE-2026-81578 are actively exploited, chaining to pre-auth RCE on the Application Server.
PaperCut issued an urgent security advisory for two actively exploited vulnerabilities, CVE-2026-82078 and CVE-2026-81578, affecting all versions of PaperCut NG and PaperCut MF. When chained, the flaws enable pre-authentication remote code execution on the PaperCut Application Server, originating from a request-confusion and authorization gap. PaperCut is widely deployed for print management in enterprises and education, making unpatched instances a high-value target.
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35 Actionable Password Statistics for Businesses in 2026 | Huntress
Huntress compiles 2026 password statistics showing 94% of 19 billion leaked passwords were reused and 37% of identity threats used stolen credentials.
Huntress published a compilation of password security statistics drawing on sources including Cybernews, Verizon's 2026 DBIR, IBM, and Bitwarden. Cybernews found 19 billion exposed passwords from roughly 200 incidents between April 2024 and April 2025, with only 6% unique and 94% reused across accounts. Huntress telemetry reports 37% of identity-based threats in 2026 involved stolen or suspicious credentials, while Verizon cites credential abuse in 39% of breaches. The piece argues weak and reused passwords remain a top entry point and recommends improved password hygiene.
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Human Attacker Hits Machine-Speed Exploitation of Marimo RCE
Sysdig details a human attacker chaining pre-auth RCE in Marimo (CVE-2026-39987) to AWS credentials and a bastion host in eight seconds.
Sysdig's Threat Research Team documented an intrusion where an operator exploited CVE-2026-39987, a pre-auth RCE in the Marimo notebook terminal WebSocket endpoint, gaining an interactive shell with no credentials. The attacker harvested AWS credentials from the process environment and Redis backend, retrieved an SSH private key from AWS Secrets Manager, and authenticated to an internet-reachable bastion host. The chain fired in eight seconds after roughly four hours of toolkit building, logging over 850 commands during a nine-hour session. The flaw, fixed in Marimo 0.23.0, has been on CISA's KEV catalog with a May 7, 2026 federal remediation deadline.
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Back-to-back N-able bugs send admins on a patching spree
CVE-2026-86218, a CVSS 10.0 pre-auth RCE in N-able N-central, is being exploited in the wild; Hotfix 4 mitigates it immediately.
N-able disclosed CVE-2026-86218 on September 6, a pre-authentication remote code execution flaw with CVSS 10.0 in its N-central RMM platform, and both N-able and Huntress report it is being exploited in the wild. It follows Huntress's disclosure of an exploit chain combining CVE-2026-86206 and CVE-2026-86207 that bypasses access controls to create unauthorized administrative accounts, investigated after a September 4 compromise of a fully patched customer environment. N-able has applied mitigations to all hosted N-central instances; on-premises customers must upgrade to Hotfix 4 (build 2026.3.1.14) immediately.
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Chrome adopts what may be the best protection yet against account takeovers
Chrome adopts device-bound session credentials that tie login sessions to a specific device, defending against cookie-theft account takeover attacks.
Chrome is adopting device-bound session credentials, which bind authenticated sessions to the physical device rather than to transferable cookies. The mechanism targets a common account takeover technique in which attackers steal session cookies and replay them on other machines. Ars Technica characterizes it as possibly the strongest protection yet against this class of takeover, which has become increasingly common.
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"WP2Shell" Critical WordPress RCE Chain (CVE-2026-63030 & CVE-2026-60137)
CISA added the WordPress core pre-auth RCE chain (CVE-2026-63030, CVE-2026-60137) to KEV after confirmed exploitation; WordPress 6.9.5 and 7.0.2 fix the flaws.
On July 17, 2026 WordPress disclosed CVE-2026-63030, a REST API route-confusion flaw, and CVE-2026-60137, a SQL injection in WP_Query, which chain to unauthenticated remote code execution on default installs of WordPress 6.9.0-6.9.4 and 7.0.0-7.0.1. CISA has added both to the Known Exploited Vulnerabilities Catalog and active exploitation is confirmed. Cloudflare deployed WAF rules at 17:03 UTC on July 17, and patches are available in WordPress 6.9.5 and 7.0.2.
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A rant about phishing: It's not the user's fault (and not DNS either)
Opinion piece argues multi-domain login redirects make legitimate flows indistinguishable from phishing, urging organizations to standardize on one recognizable root domain.
The author shows a real-world login flow that chains through numerous third-party domains (identity providers, cloud auth endpoints, OAuth APIs, 2FA pages), none on the company's own domain, so credentials and 2FA prompts are trivially impersonable. The piece argues URLs are inherently confusing because the security-relevant second-level domain sits mid-string, and that users trained to ignore URLs cannot distinguish legitimate pages from scams. It proposes RFC 2119-style requirements: single recognizable root domain, internal services on its subdomains, emailed or SMS links on that domain, and local redirects instead of third-party hosted pages.
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FST Pay: Deterministic Safety-Gated Architecture for Youth Digital Payments
FST Pay proposes a deterministic safety-gated architecture for teen digital payments, pairing invariant authorization checks with decoupled post-settlement AI explanations.
Researchers propose FST Pay, a formal architecture for adolescent digital payments on rails like UPI that applies six deterministic invariant checks (spending limits, guardian co-sign policies, amount thresholds, merchant category codes, temporal intervals, hardware integrity) to classify transactions as ALLOW, REVIEW, or BLOCK. High-risk transactions trigger an asynchronous guardian co-sign workflow. Generative AI is restricted to post-settlement natural-language insights and holds no mutation privileges over the ledger, avoiding non-determinism on the real-time authorization path.
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Weekly Cybersecurity Newsletter – Top 50 Biggest Cybersecurity Stories of the Week
GBHackers weekly digest rounds up 50 stories including Microsoft's 973-CVE patch drop, exploited Cisco FMC flaws, and Claude agent attacks.
GBHackers' September 7-12, 2026 newsletter summarizes the 50 biggest cybersecurity stories of the week. Highlights include Microsoft patching a record 973 CVEs with two exploited zero-days, active exploitation of Cisco FMC, Check Point VPN and Ivanti flaws, China-linked crews chaining Chrome and Windows zero-days, AI agents mass-exploiting PaperCut to compromise 440 servers, and the emergence of Panzer cross-platform ransomware. It also covers Anthropic and OpenAI agentic AI incidents and CrowdStrike's SafeMind launch.
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N-able patches critical N-central zero-day exploited in the wild (CVE-2026-86218)
N-able shipped an emergency hotfix for CVE-2026-86218, a pre-auth RCE zero-day in N-central RMM observed exploited in the wild.
N-able released Hotfix 4 for N-central 2026.3 on September 5 (build 2026.3.1.14), fixing CVE-2026-86218, a critical pre-authenticated remote code execution flaw in its RMM platform popular with MSPs. A private customer notice marked urgent said the zero-day 'has been observed being exploited in the wild,' while the public advisory said there were no confirmed production exploits. Huntress also flagged two high-severity vulnerabilities, CVE-2026-86206 and CVE-2026-86207, which allow authentication bypass and unrestricted access; they were patched the same weekend and were discovered by Rapid7's Stephen Fewer. N-able advised auditing N-central user accounts for unexpected users.
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Attackers are going after prominent individuals through OAuth phishing, FBI warns
FBI IC3 warns of ongoing OAuth consent phishing since late 2025 targeting prominent individuals to gain persistent, password-free account access.
Attackers register malicious applications with legitimate OAuth providers, impersonate journalists, academics, event organizers, or government officials on messaging apps and email, and lure targets into approving permission requests on real Microsoft or Google login pages. Once approved, the attacker's application can read and send emails and access sensitive files within granted permissions, bypassing both passwords and MFA. The FBI notes password changes do not revoke this access; victims must invalidate the OAuth token in application security settings, and no attribution or victim list has been disclosed.
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CISA Warns of SonicWall SMA1000 Vulnerabilities Active Exploitation (CVE-2026-83548 & CVE-2026-83549)
CISA added two actively exploited SonicWall SMA1000 flaws to KEV: pre-auth SSRF CVE-2026-83548 (CVSS 10) and post-auth RCE CVE-2026-83549; patch by September 5.
CISA added CVE-2026-83548 and CVE-2026-83549 to the Known Exploited Vulnerabilities Catalog with a September 5, 2026 patch deadline. CVE-2026-83548 is a critical (CVSS 10.0) pre-authentication SSRF in the SMA1000 Appliance Work Place interface; CVE-2026-83549 is a high (CVSS 7.8) post-authentication OS command injection leading to RCE in the Appliance Management Console. SMA1000 models 6210, 7210, and 8200v running 12.4.3-03453 or 12.5.0-02835 platform-hotfix and older are affected; fixes ship in 12.4.3-03526 and 12.5.0-02952. Qualys customers can detect vulnerable assets via QID 388624.
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Flextype v1.0.0-alpha.3 NULL access_token Authentication Bypass
Flextype CMS v1.0.0-alpha.3 API endpoints accept a NULL access_token because isset() validation lets requests bypass authentication.
Flextype CMS v1.0.0-alpha.3 API endpoints can declare access_token as a required parameter, but required-parameter validation only verifies the key exists in the request data. Authentication is then verified inside an isset($data['access_token']) condition, which in PHP treats a NULL value as absent. This allows requests supplying a NULL access_token to bypass authentication on affected endpoints. The flaw was disclosed on the Full Disclosure mailing list on September 3, 2026.
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PaperCut NG/MF vulnerabilities exploited in zero-day attacks
PaperCut warns of active zero-day exploitation chaining CVE-2026-81578 and CVE-2026-82078 for pre-auth remote code execution in NG/MF print management.
PaperCut Software confirmed attackers are chaining two vulnerabilities in PaperCut NG and MF: CVE-2026-81578, an improper access control flaw in the web management interface allowing unauthenticated configuration changes, and CVE-2026-82078, unsafe dynamic class loading in database connection utilities enabling arbitrary Java bytecode execution. Huntress reproduced a pre-authentication remote configuration takeover and full RCE chain against PaperCut NG 25.0.11.75758 and observed limited exploitation at two customers, including post-exploitation whoami and ver commands. The vendor released Emergency Patch Release 2 with additional hardening and urged restricting Application Server web access to trusted IPs. In 2023, Clop and LockBit affiliates abused CVE-2023-27350 and CVE-2023-27351 in the same software.
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Hackers Are Probing PaperCut Servers, and 47% Still Have No Patch
PaperCut pre-auth RCE CVE-2026-81578 actively exploited; 47% of tracked installs unpatched and exposed to remote code execution.
Huntress confirmed active exploitation of a pre-authentication RCE flaw in PaperCut (CVE-2026-81578), chainable with CVE-2026-82078 to achieve SYSTEM-level code execution via PaperCut's Application Server. Observed attacks focused on short reconnaissance (whoami, ver, tasklist) with no persistence, but a malicious Java class dropping into the installation directory leaves the jdbc:derby:memory:pwn breadcrumb. Roughly 47% of ~2,500 tracked installations run version 23 or earlier with no patch yet available.
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