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⚡ Weekly Recap: VMware Exploits, Windows 0-Day, MCP Attacks, Browser Hijacks and More
Weekly recap: suspected China-nexus APT exploited VMware vCenter CVE-2026-59310, Lazarus used Windows zero-day CVE-2026-68820, and macOS flaw dropped Monero miners.
The week's top stories included a suspected China-nexus APT exploiting VMware vCenter CVE-2026-59310 (CVSS 9.8), a directory-traversal flaw enabling arbitrary code execution, with backdoors, reverse SSH and Babuk-derived ransomware deployed, per QUIRSO. NCSC-NL reported active exploitation of macOS Screen Sharing flaw CVE-2026-65400 (CVSS 9.8) to install Monero miners on systems with port 5900 exposed. Lazarus Group exploited Windows zero-day CVE-2026-68820 (CVSS 7.0) in Operation Dream Job, delivering ForestTiger and Troy backdoors to defense and aerospace targets. GeoServer patched a critical SQL injection flaw exploited within hours of disclosure, and Jamf analyzed the new Amnesia Stealer for macOS with live browser control.
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Rogue ScreenConnect Installations Across Unrelated Hosts Suggest Worm-Like Activity
Huntress observed rogue ScreenConnect deployments with worm-like VBScript propagation across unrelated organizations, prompting a ConnectWise advisory on file transfer behavior.
Huntress identified multiple incidents in late August 2026 where social engineering led to rogue ScreenConnect remote access clients deployed on victim machines, which then spawned wscript.exe to run four VBScript payloads (1.vbs through 4.vbs) for profiling, telemetry collection, and persistence via a WindowsServiceHost Run key. Modified ScreenConnect clients propagated the VBScript chain to connected endpoints, creating worm-like spread. ConnectWise published an advisory on September 3, 2026, confirming an issue affecting file transfer behavior in both cloud and on-premises ScreenConnect deployments, with a CVE and fix expected within the week; partners were advised to review and disable TransferFiles permissions in the interim.
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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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CVE-2026-34486: Apache Tomcat EncryptInterceptor Fail-Open Bypass
Technical analysis shows CVE-2026-34486 is a one-line fail-open regression in Tomcat Tribes enabling unauthenticated RCE via Java deserialization.
CVE-2026-34486 is a fail-open regression in Tomcat's Tribes EncryptInterceptor, introduced while fixing the CVE-2026-29146 padding-oracle flaw; Apache rated it Important and NVD scores it 7.5 High. Decryption failures are now forwarded to an unfiltered ObjectInputStream, and public PoC repositories demonstrate unauthenticated RCE on default port 4000 when clustering, the EncryptInterceptor, a reachable receiver and deserialization gadgets are all present. Affected releases 9.0.116, 10.1.53 and 11.0.20 are fixed in 9.0.117, 10.1.54 and 11.0.21; Tomcat 8.5 is unaffected.
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Attackers Target miniOrange SAML Flaws That Can Grant WordPress Admin Access
Attackers are exploiting two unauthenticated WordPress auth bypasses (CVE-2026-61979, CVE-2026-15981, max CVSS 9.8) in miniOrange SAML SSO to gain admin sessions.
Patchstack disclosed two flaws in the Xecurify miniOrange SAML 2.0 Single Sign On WordPress plugin: CVE-2026-15981 (CVSS 9.8) accepts malformed signatures because mo_saml_validate_signature() loosely checks the tri-state result of openssl_verify(), and CVE-2026-61979 (CVSS 8.1) enables privilege escalation via signature algorithm confusion. Both let unauthenticated attackers sign in as any WordPress user, including administrators; fixes shipped in Standard edition versions 17.0.6 and 17.0.5. DigitalOcean observed an attacker using the bypass to obtain an admin session cookie, opportunistic scanning is underway from six IP addresses, and PoC chaining code is public.
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CVE-2026-16232: Check Point SmartConsole Auth Bypass
Check Point SmartConsole authentication bypass CVE-2026-16232 grants unauthenticated attackers full admin access; actively exploited and added to CISA KEV.
CVE-2026-16232 is an improper authentication flaw (CWE-287) in the Check Point SmartConsole login process that lets an unauthenticated remote attacker obtain an application token and authenticate with full administrative privileges. Exploitation requires the Management Server to be internet-reachable and the Trusted Clients list not restricted to specific administrator addresses. Check Point confirmed active exploitation affecting a small number of customers, and the vulnerability has been added to the CISA Known Exploited Vulnerabilities catalog. A hotfix is available via Check Point advisory sk185169.
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Linux Kernel Dirty Frag LPE Exploit Enables Root Access Across Major Distributions
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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.
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LiteLLM Flaws Let Attackers Execute Code as Root and Steal Cloud Credentials
Wiz disclosed LiteLLM flaws including CVE-2026-59822 MCP auth bypass, now in CISA KEV, enabling root RCE and AWS credential theft from exposed gateways.
Wiz researchers disclosed weaknesses in the open-source LiteLLM AI gateway: CVE-2026-59821 allows authenticated administrators to execute code as root via the Custom Code Guardrails feature, while CVE-2026-59822 is an MCP authentication bypass where a meaningless Bearer token establishes a valid session. The MCP bypass was observed in the wild through Wiz honeypots and added to CISA's Known Exploited Vulnerabilities catalog on September 2. A scan of 3,074 internet-facing instances found 294 (9.6%) accepting the default master key sk-1234 or lacking authentication. Fixes shipped in LiteLLM 1.82.0 (guardrail hardening) and 1.84.0 (MCP bypass); exposed instances can leak provider API keys and temporary AWS IAM credentials via the pass-through feature and metadata service, with a related config-check issue tracked as CVE-2026-35029.
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Attackers use rogue ScreenConnect clients to spread malware
Attackers deploy rogue ScreenConnect clients that spread VBScript malware to newly connected machines while ConnectWise patches a file-transfer flaw.
ConnectWise confirmed a file transfer flaw in ScreenConnect affecting both Cloud and On-Premise deployments, with a CVE identifier and official fix promised within the week; administrators can mitigate immediately by disabling TransferFiles (or TransferFilesInSession) in each role. Huntress documented incidents where social engineering installs rogue ScreenConnect clients that spawn Windows Script Host processes running four VBScript files (1.vbs-4.vbs), add a WindowsServiceHost registry Run key, and propagate to newly connected endpoints. Payloads enabled host profiling, persistence, additional ScreenConnect installs, tunneling, security-control changes, and cryptocurrency mining. ConnectWise has not confirmed a technical link between the flaw and this campaign.
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Threat Brief: OWASSRF Vulnerability Exploitation
Unit 42 details active exploitation of Exchange SSRF flaws CVE-2022-41080/CVE-2022-41082 via the OWASSRF method, deploying the SilverArrow PowerShell backdoor.
Unit 42 documents OWASSRF, an exploit chain combining CVE-2022-41080 and CVE-2022-41082 to achieve remote code execution on Microsoft Exchange via Outlook Web Access, bypassing Microsoft's ProxyNotShell mitigations. Active exploitation was observed in late November and early December 2022, affecting at least eight organizations. Attackers authenticated to Exchange, then executed a PowerShell backdoor tracked as SilverArrow to create admin accounts, install AnyDesk, tunnel RDP via PuTTY Link, and dump LSASS memory for credential theft. Exploitation is isolated rather than mass-scale because authentication is required.
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Exposed Vite servers are being probed for AWS and Azure credentials
F5 honeypots logged 32,000+ probes against Vite file-access bypass CVE-2026-39364, hunting AWS and Azure credentials on exposed dev servers.
F5 Labs reported 32,000+ scan attempts (807 attack sessions) against exposed Vite servers in August, up from 1,732 attempts over the prior three months. Attackers exploited CVE-2026-39364 (CVSS 8.2), which bypasses Vite's server.fs.deny protection via parameters like ?raw and ?import&raw, affecting Vite 7.1.0 to before 7.3.2 and Vite 8 before 8.0.5. Scanners cycled wordlists for environment files, AWS keys, Azure tokens and IaC state files, also combining older Vite CVEs (2025-30208, 2025-31125, 2024-45811) and probing a Next.js middleware bypass. Only CVE-2025-31125 is currently in CISA's KEV catalog.
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Mass Scanning Targets Exposed Vite Servers to Steal AWS Keys and Azure Tokens
Attackers mass-scanned exposed Vite dev servers exploiting CVE-2026-39364 to read .env files and steal AWS keys and Azure tokens, per F5 Labs honeynet data.
Honeynet telemetry recorded 807 session-grouped attacks and roughly 32,000 raw events in August 2026 against exposed Vite development servers. CVE-2026-39364 (CVSS 7.5) is an unauthenticated file-read flaw in Vite 7.1.0 through 7.3.2 and 8.0.5 that bypasses server.fs.deny via query parameters like ?raw and ?import&raw to return files in plaintext. Attackers also probed older Vite flaws CVE-2025-30208, CVE-2025-31125, and CVE-2024-45811, and used wordlists to locate .env files, AWS credential files, Azure token stores, and Terraform state across Linux, container, and web paths. Exposed secrets could enable lateral movement or full cloud account takeover.
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Hackers Exploit FortiGate SSL-VPN Flaw to Breach Thai ISP and Deploy MeshCentral Backdoor
Threat actors exploited FortiOS SSL-VPN flaw CVE-2024-21762 to breach Thai ISP Triple T Broadband, gaining root-level persistence via MeshCentral agents.
Attackers exploited CVE-2024-21762, an out-of-bounds write enabling unauthenticated RCE in FortiOS SSL-VPN, against Triple T Broadband's FortiGate 60F at mail.3bb.co.th, launching a Node.js reverse shell via a ROP payload. Hunt.io uncovered the operation through an exposed staging directory at 92.63.180[.]133:8888 containing 298 files of exploits, credential-harvesting scripts, session cookies, and a device inventory. Post-compromise, the actors deployed MeshCentral agents (device group TH-3BB, C2 www.ayuthayatech.com) running as root, plus a hidden SUID backdoor at /usr/local/bin/.rc, and also targeted an internal Pentaho/Tomcat server with Ghostcat (CVE-2020-1938). A cleanup script removed logs, shell histories, and web shells while deliberately preserving the MeshCentral agent and SUID backdoor.
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China-Linked Hackers Chain Chrome Zero-Day With Windows Kernel Flaw in Attacks
Volexity reports China-linked UTA0560 and JungleBamboo chained Chrome zero-day CVE-2026-85046 with kernel flaws to spy on NGOs.
Volexity documented campaigns detected on September 1, 2026, in which China-linked actors UTA0560 and JungleBamboo (APT31) chained CVE-2026-85046 (V8 type confusion), CVE-2026-87491 (WebAssembly sandbox escape), and CVE-2026-85880 (Windows kernel privilege escalation in RtlpCreateServerAcl). Victims were lured via links on legitimate U.S. university sites vulnerable to reflected XSS, then served hidden exploit iframes behind a donation-form image. Although a V8 fix had landed in Chromium's source after private August reporting, Chrome had not yet shipped it, creating a patch gap the actors exploited. The two groups installed distinct payloads: UTA0560 delivered the GRIMWEDGE JScript backdoor via DLL side-loading, while JungleBamboo used the SUPERSTOMP loader to install the LONGTALE credential-stealing Chrome extension disguised as Google Gemini.
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CISA Warns of Citrix NetScaler Authentication Bypass Vulnerability Exploited in Attacks
CISA adds exploited Citrix NetScaler authentication bypass CVE-2026-19490 to the KEV catalog; federal agencies must patch by September 12.
CISA added CVE-2026-19490, a CWE-288 authentication bypass affecting NetScaler ADC and Gateway deployments configured as AAA virtual servers or Gateway services (including SSL VPN, ICA Proxy, and RDP Proxy), to the Known Exploited Vulnerabilities catalog. Citrix released fixes on August 19, 2026; honeypots recorded 56 attack attempts between September 3 and 8 after a public PoC, though no confirmed production compromises have been reported. Affected builds include 14.1 before 14.1-73.32 and 13.1 before 13.1-63.21; newer installations require SAML IdP configuration to be exposed.
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