FreeBSD : FreeBSD -- Kernel use-after-free via the SNDCTL_DSP_SYNCSTART ioctl (226751fb-a0fe-11f1-ae1f-bc241121aa0a)

high Nessus Plugin ID 340054

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Synopsis

The remote FreeBSD host is missing one or more security-related updates.

Description

The version of FreeBSD installed on the remote host is prior to tested version. It is, therefore, affected by a vulnerability as referenced in the 226751fb-a0fe-11f1-ae1f-bc241121aa0a advisory.

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.

Tenable has extracted the preceding description block directly from the FreeBSD security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

Solution

Update the affected packages.

See Also

http://www.nessus.org/u?2f1dd65c

Plugin Details

Severity: High

ID: 340054

File Name: freebsd_pkg_226751fba0fe11f1ae1fbc241121aa0a.nasl

Version: 1.1

Type: Local

Published: 8/26/2026

Updated: 8/26/2026

Configuration: Enable paranoid mode

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.9

Percentile: 58.17

CVSS v2

Risk Factor: Medium

Base Score: 4.6

Temporal Score: 3.4

Vector: CVSS2#AV:L/AC:L/Au:N/C:P/I:P/A:P

CVSS Score Source: CVE-2026-58091

CVSS v3

Risk Factor: High

Base Score: 7.8

Temporal Score: 6.8

Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

CPE: cpe:/o:freebsd:freebsd, p-cpe:/a:freebsd:freebsd:freebsd-kernel

Required KB Items: Host/local_checks_enabled, Settings/ParanoidReport, Host/FreeBSD/release, Host/FreeBSD/pkg_info

Exploit Ease: No known exploits are available

Patch Publication Date: 8/26/2026

Vulnerability Publication Date: 8/26/2026

Reference Information

CVE: CVE-2026-58091