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VulnerabilityPublished Updated

CVE-2026-5398: FreeBSD · Use After Free

Affects FreeBSDSource GCVE Database

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Not known to be exploited · CVSS 8.4 High.

Data as of 12 Nov 2026, 00:47 UTC

CVSS 3.1 base score
8.4High
How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none
CVSS scores by source
CISA-ADPCVSS 3.18.4
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 22 Apr 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 11 Nov 2026.

What to do

Affected software

ProductAffectedFixed in
Freebsdfreebsd/freebsdpkg:deb/freebsd/freebsdOther threatsAffected
  • 13.5-RELEASE – 15.0-RELEASE
4 affected builds
Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Until a fix is available, restrict untrusted users from invoking TIOCNOTTY or limit access to vulnerable FreeBSD versions.

Description

CVE-2026-5398 is a use-after-free vulnerability in FreeBSD related to the TIOCNOTTY ioctl implementation. The flaw occurs because the back-pointer from the controlling terminal structure to the calling process' session is not cleared properly. If the process exits, the terminal structure may hold a dangling pointer to freed memory. This can be exploited by a malicious process to gain root privileges. The vulnerability affects specific FreeBSD releases including 15.0-RELEASE, 14.4-RELEASE, 14.3-RELEASE, and 13.5-RELEASE. It has a high severity with a CVSS score of 8.4.

References

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