Kernel use-after-free via the SNDCTL_DSP_SYNCSTART ioctl (CVE-2026-58091) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-58091

Kernel use-after-free via the SNDCTL_DSP_SYNCSTART ioctl

Answer in brief

CVE-2026-58091 records a Unknown severity vulnerability in Kernel use-after-free via the SNDCTL_DSP_SYNCSTART ioctl. The current sources do not mark it as known exploited. The current feed maps FreeBSD/FreeBSD (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Aug 26, 2026Updated Aug 26, 2026Source checked Aug 26, 2026First seen by HOL Aug 26, 2026Material review Aug 26, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps FreeBSD/FreeBSD (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
FreeBSD/FreeBSDgeneric	>=15.1-RELEASE <p3 \|\| >=15.0-RELEASE <p13 \|\| >=14.4-RELEASE <p9	p3, p13, p9

Recommended response

Check inventory. Check lockfiles and deployed manifests for FreeBSD/FreeBSD.
Review the reported fix. Update FreeBSD/FreeBSD to p3 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Aug 26, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Aug 26, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Aug 26, 2026

Sources and claim methodology

Source referencesecurity.freebsd.org

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.