Vulnerability in FreeBSD

[ Description ]Official description

When copying knotes from a parent kqueue to a child, the copy code did not correctly exclude marker knotes (used internally to track list traversal position) before marking them as in-flux and releasing the kqueue lock. If another thread freed a marker while the lock was dropped, the subsequent in-flux decrement operated on freed memory. An unprivileged local user may be able to exploit these races to escalate privileges.

[ Fixes ]Fixes and patches

No fix or interim patch is linked from our sources yet. Check the vendor references below and limit exposure of affected systems until a fix is available.

[ Advisories ]Government CERT advisories

• BSI CERT-Bund29 Sep 2026WID-SEC-2026-3664

  FreeBSD Project FreeBSD OS: Multiple vulnerabilities Translated from German

  CVE-2026-84783CVE-2026-101305CVE-2026-101306+7 more CVEs

[ References ]References

• security.freebsd.org/advisories/FreeBSD-SA-26:65.kqueue.ascVendor Advisory