CVE-2026-58093

Local privilege escalation via tty revalidation race

Published Aug 26, 2026 · Updated Aug 27, 2026

Use-after-free in the FreeBSD tty subsystem allows local users to escalate privileges through a race in terminal ioctl handling. TIOCSCTTY drops the tty lock for the process tree lock, then links the terminal to a session without revalidating it after relocking, even if another thread is destroying it. An unprivileged local account must win the race; successful exploitation elevates privileges through the kernel.

CVSS severity7.0
High
EPSS probability0.09%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Use-after-free in the FreeBSD tty subsystem allows local users to escalate privileges through a race in terminal ioctl handling. TIOCSCTTY drops the tty lock for the process tree lock, then links the terminal to a session without revalidating it after relocking, even if another thread is destroying it. An unprivileged local account must win the race; successful exploitation elevates privileges through the kernel.

The record

CVE
CVE-2026-58093
Published
Aug 26, 2026
Updated
Aug 27, 2026
Vendor
The FreeBSD Project
Product
FreeBSD
Classifications
CWE-362, 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

Compare your product and version with the public record. A matching version still requires validation against your environment.

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

6.6TenableAV:L/AC:M/Au:N/C:C/I:P/A:C
7.0TenableCVSS:3.1/AV:L/AC:H/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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-362Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo