CVE-2026-58090

Local privilege escalation via retained freed control mbufs

Published Aug 26, 2026 · Updated Aug 27, 2026

Use-after-free in the UNIX-domain SOCK_STREAM receive path in FreeBSD 15.0 and 15.1 allows local users to escalate privileges. The receive path processes ancillary control-message mbufs before fully detaching them from the socket buffer, while error cleanup frees mbufs that remain referenced there. Unprivileged local access is sufficient to trigger the stale kernel-buffer reference and obtain elevated privileges.

CVSS severityUnavailable
Unscored
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 UNIX-domain SOCK_STREAM receive path in FreeBSD 15.0 and 15.1 allows local users to escalate privileges. The receive path processes ancillary control-message mbufs before fully detaching them from the socket buffer, while error cleanup frees mbufs that remain referenced there. Unprivileged local access is sufficient to trigger the stale kernel-buffer reference and obtain elevated privileges.

The record

CVE
CVE-2026-58090
Published
Aug 26, 2026
Updated
Aug 27, 2026
Vendor
The FreeBSD Project
Product
FreeBSD
Classifications
CWE-416, T1068
Attack vector
local
Privileges
Unavailable

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=15.0-RELEASE <p13
  2. Affected versionversion=15.1-RELEASE <p3

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

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

Published CVSS scores

No CVSS assessment is available in this record.

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
PrivilegesUnavailable
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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