CVE-2026-101308

TOCTOU race between sound(4) buffer resizing and mmap

Published Oct 15, 2026 CVSS 3.1 · 5.5 Medium EPSS < 1% KEV · Not listed
Description
When an audio channel's buffer needs to be resized, the sound(4) driver checks that the buffer is not memory-mapped and then drops the channel lock to allocate a new buffer. An mmap(2) call on another thread can complete during this window, after which the resize path frees the now-mapped buffer without rechecking.

An unprivileged local user with access to a sound device can exploit this race to trigger a use-after-free in the kernel, potentially escalating privileges.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
CPEs cpe:2.3:o:freebsd:freebsd:14.4:-:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:14.4:p10:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:14.4:p1:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:14.4:p2:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:14.4:p3:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:14.4:p4:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:14.4:p5:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:14.4:p6:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:14.4:p7:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:14.4:p8:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:14.4:p9:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:14.5:-:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:14.5:p1:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:15.1:-:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:15.1:p1:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:15.1:p2:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:15.1:p3:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:15.1:p4:*:*:*:*:*:*
Type Values Removed Values Added
First Time appeared Freebsd
Freebsd freebsd
Vendors & Products Freebsd
Freebsd freebsd
Type Values Removed Values Added
Metrics cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description When an audio channel's buffer needs to be resized, the sound(4) driver checks that the buffer is not memory-mapped and then drops the channel lock to allocate a new buffer. An mmap(2) call on another thread can complete during this window, after which the resize path frees the now-mapped buffer without rechecking. An unprivileged local user with access to a sound device can exploit this race to trigger a use-after-free in the kernel, potentially escalating privileges.
Title TOCTOU race between sound(4) buffer resizing and mmap
Weaknesses CWE-367
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
freebsd
Published
Updated
Oct 15, 2026, 3:40 PM
Reserved
Sep 28, 2026, 1:33 PM
Status
Analyzed
Published
Oct 15, 2026, 7:17 AM
Modified
Oct 19, 2026, 9:07 PM