The skb that wasn't freed - the Fragnesia primitive via Open vSwitch
Doyensec details CVE-2026-90049 in Open vSwitch, enabling deterministic Linux kernel local privilege escalation on default major distribution installs.
Doyensec reports that the Open vSwitch datapath strips the SKBFL_SHARED_FRAG flag from packets it is still forwarding, allowing an in-place decrypt to write attacker-chosen bytes into root-owned page cache — a Dirty COW-class primitive that re-opens the Fragnesia bug family. The issues are tracked as CVE-2026-90049, CVE-2026-89487, and CVE-2026-80977, and were reported to the kernel security team with fixes coordinated alongside OVS maintainers. A deterministic local privilege escalation works on default installs of Arch, Fedora, Debian, Amazon Linux, and RHEL where unprivileged user namespaces and openvswitch auto-loading are enabled; the fix landed in mainline and shipped in stable on 09/04/2026. The write technique builds on the earlier Fragnesia and Dirty Frag bugs, including CVE-2026-43284 and CVE-2026-43500.
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.