CVE-2026-58083 Use-after-free in kqueue copy-on-fork

While the kernel was copying knotes during fork, a knote with a timer-based filter could fire and be enqueued on the kqueue's active list before the copy was complete. The copy routine did not account for this and could enqueue the new knote a second time, corrupting the active list. In addition,...

FreeBSD-SA-26:50.kqueue

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 ============================================================================= FreeBSD-SA-26:50.kqueue Security Advisory The FreeBSD Project Topic: Use-after-free in kqueue copy-on-fork Category: core Module: kqueue Announced: 2026-07-29 Credits:...

FreeBSD -- Use-after-free in kqueue copy-on-fork

Problem Description: While the kernel was copying knotes during fork, a knote with a timer-based filter could fire and be enqueued on the kqueue's active list before the copy was complete. The copy routine did not account for this and could enqueue the new knote a second time, corrupting the acti...