Vulnerability · Published Aug 26, 2026 · Assigned by freebsd

CVE-2026-58091Kernel use-after-free via the SNDCTL_DSP_SYNCSTART ioctl

High 7.8

In plain English

A high-severity use-after-free in FreeBSD from FreeBSD. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 5% of all known vulnerabilities).

Severity (CVSS 3.1)7.8High

Exploit odds (30 days)0.2%top 95.5% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

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.

Affected products (as reported)

Vendor	Product	Versions
FreeBSD	FreeBSD	15.1-RELEASE – before p315.0-RELEASE – before p1314.4-RELEASE – before p9

Weakness: CWE-416 · Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

References

https://security.freebsd.org/advisories/FreeBSD-SA-26:58.sound.asc vendor-advisory