Cisco patches Secure Email Gateway zero-day exploited in attacks
Cisco patches actively exploited Secure Email Gateway zero-day CVE-2026-76461 enabling unauthenticated root command execution; CISA adds it to KEV.
Cisco disclosed that a critical zero-day (CVE-2026-76461) in the email parsing logic of AsyncOS for Secure Email Gateway is being actively exploited, allowing unauthenticated remote attackers to execute arbitrary SQL statements that lead to root-level command execution on virtual and physical appliances. CISA added the flaw to its KEV catalog and ordered federal agencies to patch within three days, by September 17. Cisco also patched four other critical SEG/SEWM vulnerabilities (CVE-2026-76440, CVE-2026-76441, CVE-2026-20353, CVE-2026-76443) with no evidence of exploitation, and shared IOCs including suspicious SQL statements in mail_logs.
One Click on a Malicious Link Lets Hackers Backdoor Sogou Input Method Users
Actively exploited one-click flaw in Sogou Input Method (CVE-2026-51990) let UNC3569 deploy the GRAYRABBIT espionage backdoor on Windows.
Gen Digital researchers found three weaknesses in Sogou Input Method's sgbiz protocol handler that chain into a one-click RCE running with the signed-in user's permissions. UNC3569 used the chain in an active intrusion, leveraging an unsandboxed Chromium 80 embedded browser, the known V8 flaw CVE-2021-38003, and DLL sideloading via 7-Zip to deploy the GRAYRABBIT backdoor. Tencent fixed the issue in version 16.3.0.3498 within 12 days of disclosure; Sogou is used by hundreds of millions of people, mainly in China.
ShieldBreak Zero-Day PoC Claims Microsoft Defender Patch Bypass With SYSTEM Access
Researcher Chaotic Eclipse released ShieldBreak PoC, a claimed patch bypass for Microsoft Defender flaw CVE-2026-50656, now tracked as CVE-2026-69414.
Researcher Chaotic Eclipse released a PoC for ShieldBreak, a claimed full patch bypass of Microsoft Defender flaw CVE-2026-50656 (RoguePlanet), which can yield SYSTEM privileges. Independent researchers Kevin Beaumont and Will Dormann validated the exploit on Windows 11 25H2 and Windows Server 2025, noting it requires Defender to be enabled. Microsoft assigned CVE-2026-69414 (CVSS 7.8) with an 'Exploitation More Likely' assessment and is investigating, but has not yet released a patch. The article also notes CISA's KEV addition of the actively exploited Windows AFD.sys flaw CVE-2026-68820.
Critical Issabel PBX Command Execution Vulnerability Exploited in the Wild
Unauthenticated attackers exploit CVE-2026-89026 in Issabel PBX via forged JWT tokens to run OS commands; exploitation observed since September 9.
CVE-2026-89026 (CVSS v4 9.3) stems from a hard-coded HS256 JWT signing key in Issabel Framework's pbxapi/index.php, letting unauthenticated attackers forge bearer tokens and execute OS commands through the Asterisk Manager Interface originate endpoint. Issabel Framework versions before commit b97dbaf0b71c1c36f841e672b664afbeb02773bd are affected. Shadowserver Foundation first observed exploitation on September 9, 2026, and VulnCheck added the flaw to its Known Exploited Vulnerabilities database.