CVE-2026-58083Use-after-free in kqueue copy-on-fork
Updated under an hour ago ()
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It affects FreeBSD. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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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, the copy routine did not hold the appropriate locks while reading knote state, allowing further races. An unprivileged local user can trigger a use-after-free in the kernel, potentially leading to privilege escalation.
- CVSS
- 8.4 HIGH (v3.1, CISA ADP)CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Weakness (CWE)
- CWE-416
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- freebsd
- NVD analysis
- Analyzed
- Record last updated
- Aug 20, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
FreeBSD FreeBSD freebsd:freebsd (from the name) | from 15.1-RELEASE before p2 | CNA record |
freebsd freebsd freebsd:freebsd | 15.1; 15.1; 15.1; 15.1 | NVD |
References
- https://security.freebsd.org/advisories/FreeBSD-SA-26:50.kqueue.ascvendor-advisory
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.