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Fencer Vulns
high 7.8

CVE-2026-58091 json

Kernel use-after-free via the SNDCTL_DSP_SYNCSTART ioctl

published 2026-08-26 2 mo ago modified 2026-09-24 46 d ago also EUVD-2026-66236

cvss
7.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 4%
public exploits
0
none known

Summary

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.

Patch / fix

  • FreeBSD FreeBSD p3, p9, p13

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
2 mo ago

Exploit prediction

0.15% chance of exploitation in the next 30 days, higher than 4% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CNA 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

  • FreeBSD FreeBSD

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.