CVE-2026-5398: FreeBSD · Use After Free
Affects FreeBSDSource GCVE Database
Not known to be exploited · CVSS 8.4 High.
Data as of 12 Nov 2026, 00:47 UTC
Thin evidence
One scorer or none| CISA-ADP | CVSS 3.1 | 8.4 |
|---|
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 22 Apr 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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
| Product | Affected | Fixed in |
|---|---|---|
Freebsdfreebsd/freebsdpkg:deb/freebsd/freebsdOther threats | Affected
| 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.