September 2026 Patch Tuesday roundup: Plugs for two zero day holes among almost 1,000 fixes in Windows
Microsoft's September 2026 Patch Tuesday ships 964 fixes including two exploited Windows zero-days (CVE-2026-85880, CVE-2026-81963) and a wormable DNS RCE.
Microsoft's September 2026 Patch Tuesday includes 964 Microsoft vulnerabilities requiring customer action, a record attributed to AI-assisted bug discovery, plus 174 third-party/open-source and 23 Chromium/Edge CVEs. Two zero-days are exploited in the wild: CVE-2026-85880, a Windows ALPC heap overflow enabling AppContainer sandbox escape and privilege escalation, and CVE-2026-81963, a Windows Update Stack escalation to SYSTEM. CVE-2026-69730, an unauthenticated Windows DNS RCE, is not yet exploited but Microsoft expects exploitation, and roughly 20 bugs could be wormable. Separately, SAP issued a critical CVSS 10.0 fix for the EPP component used in S/4HANA and NetWeaver.
More than 200 victims of Medusa ransomware identified over the last year, CISA says
CISA and FBI update Medusa ransomware advisory, reporting more than 500 total victims and warning the gang operationalizes newly disclosed exploits within 24 hours.
CISA and the FBI updated their March 2025 advisory, stating Medusa actors had hit more than 500 victims as of April 2026, up from 300 in 2025, with a focus on healthcare and critical infrastructure. The agencies say Medusa rapidly adopts newly announced exploits, sometimes using them up to a week before public vulnerability disclosure, but does not develop its own zero-days, preferring access obtained from unknown sources. The gang moved to an affiliate model in 2023, offers up to $1 million for exclusive initial access brokers, and uses credential stealers plus legitimate remote access tools including AnyDesk, Atera, ConnectWise and Splashtop. No new victims have appeared on its leak site since April, after the shutdown of the University of Mississippi Medical Center drew significant law enforcement attention.