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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.

Microsoft Releases Emergency Windows 11 Update Following Patch Tuesday Bugs

Microsoft issued emergency Windows 11 update KB5129195 to fix Patch Tuesday regressions and fully close the CVE-2026-62721 privilege escalation flaw.

Microsoft shipped out-of-band cumulative update KB5129195 for Windows 11 24H2 and 25H2 (builds 26100.9457 and 26200.9457) after the September 8 Patch Tuesday rollup, which addressed over 960 CVEs including two actively exploited flaws, broke Remote Desktop Services, Hyper-V Plan9 folder sharing, and USB audio. The emergency release also strengthens the incomplete fix for CVE-2026-62721, an elevation-of-privilege flaw in the Windows User-Mode Power Service that could let a local attacker gain SYSTEM privileges. Companion patches cover Windows 11 26H1, Windows 10, and Windows Server. Some USB Audio Class 1.0 and AMD Radeon graphics issues remain unresolved.

Cyber Security News · 8h agoVulnerability in the wildCVE-2026-62721

Attackers Chain Two PaperCut Flaws to Execute Code Without Authentication

Attackers chain PaperCut NG/MF flaws CVE-2026-81578 and CVE-2026-82078 for unauthenticated RCE; exploitation observed and a second emergency patch issued.

Two flaws in PaperCut NG and MF — CVE-2026-81578 (CVSS 8.8, improper access control enabling auth bypass) and CVE-2026-82078 (CVSS 9.4, unsafe dynamic class loading) — are being chained for unauthenticated remote code execution. Huntress observed limited exploitation on two customer environments, including Base64-encoded commands, 'whoami & ver' fingerprinting, SimpleHelp execution, and AnyDesk installation for persistence. PaperCut released a second emergency patch for v24, v25, and v26, but watchTowr reports additional patch bypasses may still affect the latest version. Shared IoCs include crafted jdbc strings in server.log and attacker-written .class/.cmd files.

The Hacker News · 14d agoExploit / PoC in the wildCVE-2026-82078CVE-2026-815781

PaperCut Replaces Emergency Patches With Fixes for Two Actively Exploited Flaws

PaperCut shipped maintenance releases replacing emergency patches for two actively exploited flaws abused in AI-assisted attacks on 395 organizations.

PaperCut released PaperCut NG/MF versions 26.0.5, 25.0.13 and 24.1.10, superseding Emergency Patch Releases 1-3 for CVE-2026-81578 and CVE-2026-82078, which enable authentication bypass and arbitrary code execution on susceptible instances. GreyNoise and Blackpoint Cyber reported a suspected Russian-speaking actor weaponizing both flaws against at least 395 organizations in 48 countries, concentrated in the U.S. education sector. The campaign used hundreds of AI agents powered by OpenAI's Codex harness and a DeepSeek model, originating from IP 45.142.193.132, and avoided organizations in Russia, China, Hong Kong, Thailand and Iran.

The Hacker Newsupdated · 5d agofirst · 5d agoExploit / PoC in the wild 7 sourcesCVE-2026-81578CVE-2026-820781

CVE-2026-34486: Apache Tomcat Auth Bypass Vulnerability

SentinelOne details CVE-2026-34486, an Apache Tomcat EncryptInterceptor bypass exposing unencrypted cluster communications, with patches and workarounds available.

CVE-2026-34486 stems from an incomplete fix for CVE-2026-29146, letting network-positioned attackers bypass the EncryptInterceptor and read plaintext Tomcat cluster traffic, including session and application data between nodes. Affected versions 9.0.116, 10.1.53 and 11.0.20 are fixed in 9.0.117, 10.1.54 and 11.0.21. Workarounds include network-level encryption such as IPsec or VPN tunnels and isolating cluster communications to secured network segments.

SAP September 2026 Security Update Fixes 4 Critical Vulnerabilities and 15 Other Flaws

SAP's September 2026 Patch Tuesday ships 19 security notes, including four criticals led by a CVSS 10.0 memory-corruption flaw in Extended Passport Processing.

SAP released 19 new Security Notes plus one update, fixing four critical vulnerabilities and 15 additional flaws. The most urgent is CVE-2026-44756 (CVSS 10.0), memory corruption in Extended Passport (EPP) Processing affecting many SAP Kernel and Web Dispatcher releases. Other criticals include CVE-2026-58240 (NetWeaver Message Server missing authentication, 9.8), CVE-2026-76969 (credential disclosure in CAP sap/cds-mtxs, 9.4), and CVE-2026-66768 (improper access control in SAP GUI for Java, 9.0). High-severity fixes cover XXE in Integration Suite Trading Partner Management, deserialization in NetWeaver Business Client, and memory corruption in NetWeaver AS for ABAP.

Attackers Hijack MikroTik Routers Through Internet-Exposed SSH Without Authentication

CERT Polska warns attackers exploit internet-exposed MikroTik SSH for unauthenticated full admin control; attacks observed since at least September 2.

CERT Polska warned on September 5 that attackers exploit MikroTik routers with internet-reachable SSH to gain full administrative control without authentication, calling the two-flaw combination 'MikroTrick'. Successful attacks date to at least September 2; no victim count or attacker identity was disclosed. MikroTik shipped fixed RouterOS releases: 6.49.21, 7.23.4 (with 7.23.5 fixing an IPv6 DHCP regression), 7.24.2, and 7.25beta3. CERT recommends immediate updates, checking for unauthorized configuration changes, and restricting SSH, WWW/WWW-SSL, and bandwidth-test services on unpatched devices.

The Hacker News · 10d agoExploit / PoC in the wild

Attackers plant remote access tools on compromised PaperCut servers

Attackers chained two PaperCut NG/MF zero-days for unauthenticated access, installing SimpleHelp and AnyDesk remote access tools on compromised servers.

An ongoing campaign exploits chained zero-days CVE-2026-81578 (improper access control) and CVE-2026-82078 (unsafe dynamic class loading) in internet-facing PaperCut NG and MF Application Servers, enabling authentication bypass and arbitrary Java bytecode execution. Post-compromise activity includes user and domain enumeration, payload download from sendit.sh, and silent installation of SimpleHelp and AnyDesk for redundant remote access; Defused observed CVE-2026-81578/CVE-2026-82078 exploit activity in honeypots since August 29, including data theft via Derby database dumps. Emergency patches were released August 28 and August 30, but 47% of roughly 2,500 PaperCut installs tracked by Huntress run v23 or older, for which no patch is available.

Help Net Security · 14d agoExploit / PoC in the wildCVE-2026-81578CVE-2026-820781

Marimo Notebook Flaw Could Run MCP Commands Before Cells Execute in Edit Mode

Marimo notebook flaw CVE-2026-75149 (CVSS 8.7) allows attacker-supplied MCP commands to run as local subprocesses before any cell executes in edit mode.

Marimo addressed CVE-2026-75149, a high-severity code injection flaw allowing attacker-supplied Model Context Protocol (MCP) commands to execute as local subprocesses when a crafted notebook is opened in edit mode, before any cell runs. The issue affects versions prior to 0.23.15, carries CVSS v4 of 8.7 and CVSS v3.1 of 8.8, and requires user interaction but no authentication. Marimo fixed it in version 0.23.15 (released July 23, 2026) via a PEP 723 hardening patch that treats notebook metadata as attacker-controlled and strips ai, mcp, completion, secrets, and server configuration sections. VulnCheck's CNA also disclosed CVE-2026-67618 (CVSS 7.1), involving an attacker-controlled AI base_url that exfiltrates operator API keys, and earlier CVE-2023-39987, a missing auth on /terminal/ws endpoint allowing full PTY shell access.

NASA AIT-GUI Flaws Could Let Unauthenticated Attackers Issue Spacecraft Commands

Researchers disclosed 9.4-CVSS flaws in NASA/JPL's AIT-GUI allowing unauthenticated attackers to issue arbitrary spacecraft commands via exposed command endpoints.

Cycode disclosed a flaw chain in AIT-GUI, the browser-based operator console for NASA/JPL's open-source AMMOS Instrument Toolkit, tracked as GHSA-p9r8-2q67-fp86 with CVSS 9.4, affecting versions 2.5.1 and earlier. The server binds to 0.0.0.0:8080, issues sessions without credential checks, and lets unauthenticated users issue spacecraft commands via POST /cmd and reach files outside intended directories via /script/run and /seq (CWE-306, CWE-352, CWE-22). Version 2.5.2 adds host binding and same-origin checks but does not add authentication, and a related missing-authentication flaw was published separately as CVE-2026-60112 with CVSS 9.3.

The Hacker News · 26d agoVulnerabilityCVE-2026-601121