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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.

Huntress · 18d agoExploit / PoC in the wild

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.

The Hacker Newsupdated · 1d agofirst · 6d agoExploit / PoC in the wild 5 sourcesCVE-2026-86218CVE-2026-86206CVE-2026-86207

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.

The Hacker News · 13d agoResearchCVE-2021-318862

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.

watchTowr Labs · Aug 14, 2026Exploit / PoCCVE-2026-8452

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.

The Hacker News · 27d agoExploit / PoC in the wildCVE-2026-65400CVE-2026-43779CVE-2026-43777+1 CVEs

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.

Huntress · 9d agoExploit / PoC in the wildCVE-2026-86218CVE-2026-86206CVE-2026-86207+2 CVEs

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.

Security Affairs · 13d agoExploit / PoC in the wildCVE-2026-83548CVE-2026-83549CVE-2026-15409+1 CVEs1

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.

Horizon3.ai · 14d agoExploit / PoC in the wildCVE-2026-81578CVE-2026-820781

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.

Palo Alto Unit 42 · 27d agoExploit / PoC in the wildCVE-2020-25506CVE-2020-26919CVE-2019-19356+3 CVEs

Human Attacker Exploits Marimo RCE, Reaches SSH Bastion in Eight Seconds

Sysdig documents a skilled human attacker exploiting Marimo pre-auth RCE CVE-2026-39987 (CVSS 9.3), reaching an SSH bastion in eight seconds without AI tooling.

Sysdig detailed exploitation of CVE-2026-39987 (CVSS 9.3), a pre-authenticated RCE affecting all Marimo versions that came under active exploitation within hours of disclosure. A human operator used a hand-written Python script to harvest an AWS key from Secrets Manager and SSH into a bastion host in eight seconds, issuing 850+ commands over nine hours. Separately, Hunt.io disclosed an XMRig cryptomining campaign compromising 3,562 Redis servers via SLAVEOF rogue replication and AOF authorized_keys injection. Operation CameraSwarm, linked to a single operator, compromised over 14,000 Dahua IP cameras using CVE-2021-33044 and CVE-2021-33045.

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.

GBHackers · 11h agoIndustry in the wild

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.

oss-security · 2d agoVulnerabilityCVE-2026-824353

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.

Wiz Blogupdated · 5d agofirst · 6d agoExploit / PoC in the wild 4 sourcesCVE-2026-59822CVE-2026-598211

"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.

2026-008: Critical vulnerabilities in Ivanti Sentry

Ivanti patched Sentry: pre-auth OS command injection CVE-2026-10520 (CVSS 10) enables unauthenticated root RCE, and auth bypass CVE-2026-10523 (CVSS 9.9).

On 9 June 2026 Ivanti released an advisory fixing two critical flaws in Ivanti Sentry versions 10.5.1 and prior, 10.6.1 and prior, and 10.7.0 and prior. CVE-2026-10520 (CVSS 10.0) is an OS command injection allowing a remote unauthenticated attacker to achieve root-level RCE. CVE-2026-10523 (CVSS 9.9) is an authentication bypass letting an unauthenticated attacker create arbitrary administrative accounts and obtain full admin access. CERT-EU recommends updating appliances to fixed versions following Ivanti's guidance.

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.

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.

CSO Online · 8d agoExploit / PoC in the wildCVE-2026-86218CVE-2026-86206CVE-2026-86207+2 CVEs

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.