High severity · published Apr 22, 2026
CVE-2026-5398
Kernel use-after-free bug in the TIOCNOTTY handler
8.4
CVSS
0.2%
EPSS
No
On KEV
Description
The implementation of TIOCNOTTY failed to clear a back-pointer from the structure representing the controlling terminal to the calling process' session. If the invoking process then exits, the terminal structure may end up containing a pointer to freed memory.
A malicious process can abuse the dangling pointer to grant itself root privileges.
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Local
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 11% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
FR
FreeBSD · FreeBSD
15.0-RELEASE before p6; 14.4-RELEASE before p2; 14.3-RELEASE before p11; 13.5-RELEASE before p12 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-5398
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-5398
Vendor Advisory
https://security.freebsd.org/advisories/FreeBSD-SA-26:10.tty.asc
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