Use After Free in FreeBSD

CVE-2026-58091

The implementation of this ioctl attempts to acquire locks on all channels in a sync group. If locking a channel would block, it releases the sync group list lock and sleeps. Upon reawakening, it is possible that the sync group structure is freed, but the implementation did not handle this possibility. On a system with a multiple audio devices, an unprivileged local user can exploit this use-after-free to escalate privileges.

Vulnerability class: Use-After-Free

Published · last modified .

CVSS v3 metric

CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.002 (4.0th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 4th percentile — 4.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-58091: held from 0.001 to 0.002.

EPSS over last 30 days · oldest: 0.001 · newest: 0.002 · change: +0.000

Affected products

  • FreeBSD — versions 15.0, 14.4, 15.1

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-58091?
CVE-2026-58091 is a high-severity vulnerability in FreeBSD, classified under Use After Free. CVSS score: 7.8/10. Published 2026-08-26.
How severe is CVE-2026-58091?
High severity. CVSS v3 base score is 7.8 out of 10.