CVE-2026-58091

Local privilege escalation via freed sync-group reuse

Published Aug 26, 2026 · Updated Aug 27, 2026

Use-after-free in the FreeBSD sound(4) driver allows local users to gain kernel privileges through SNDCTL_DSP_SYNCSTART. The dsp_oss_syncstart function drops the sync-group lock and sleeps when a channel lock would block, then can resume with a sync-group structure freed during that interval. Exploitation requires multiple audio devices and unprivileged local access; systems with zero or one sound device are unaffected.

CVSS severity7.8
High
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in the FreeBSD sound(4) driver allows local users to gain kernel privileges through SNDCTL_DSP_SYNCSTART. The dsp_oss_syncstart function drops the sync-group lock and sleeps when a channel lock would block, then can resume with a sync-group structure freed during that interval. Exploitation requires multiple audio devices and unprivileged local access; systems with zero or one sound device are unaffected.

The record

CVE
CVE-2026-58091
Published
Aug 26, 2026
Updated
Aug 27, 2026
Vendor
The FreeBSD Project
Product
FreeBSD
Classifications
CWE-416, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 26, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 27, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=14.4-RELEASE <p9
  2. Affected versionversion=15.0-RELEASE <p13
  3. Affected versionversion=15.1-RELEASE <p3

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The FreeBSD Project · FreeBSDversion=14.4-RELEASE <p9; version=15.0-RELEASE <p13; version=15.1-RELEASE <p3

Published CVSS scores

7.8CISA-ADPCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free
T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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