Kernel use-after-free bug in the TIOCNOTTY handler

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Summary

CVECVE-2026-5398
StatePUBLISHED
Assignerfreebsd
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-04-22 03:16:01 UTC
Updated2026-05-01 12:49:44 UTC
DescriptionThe 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.

Risk And Classification

Primary CVSS: v3.1 8.4 HIGH from ADP

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS: 0.000170000 probability, percentile 0.042940000 (date 2026-05-05)

Problem Types: CWE-416 | CWE-416 CWE-416: Use After Free

VersionSourceTypeScoreSeverityVector
3.1ADPDECLARED8.4HIGHCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
3.1134c704f-9b21-4f2e-91b3-4a467353bcc0Secondary8.4HIGHCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Operating System Freebsd Freebsd 13.5 - All All
Operating System Freebsd Freebsd 13.5 beta3 All All
Operating System Freebsd Freebsd 13.5 p1 All All
Operating System Freebsd Freebsd 13.5 p10 All All
Operating System Freebsd Freebsd 13.5 p11 All All
Operating System Freebsd Freebsd 13.5 p2 All All
Operating System Freebsd Freebsd 13.5 p3 All All
Operating System Freebsd Freebsd 13.5 p4 All All
Operating System Freebsd Freebsd 13.5 p5 All All
Operating System Freebsd Freebsd 13.5 p6 All All
Operating System Freebsd Freebsd 13.5 p7 All All
Operating System Freebsd Freebsd 13.5 p8 All All
Operating System Freebsd Freebsd 13.5 p9 All All
Operating System Freebsd Freebsd 14.3 - All All
Operating System Freebsd Freebsd 14.3 p1 All All
Operating System Freebsd Freebsd 14.3 p10 All All
Operating System Freebsd Freebsd 14.3 p2 All All
Operating System Freebsd Freebsd 14.3 p3 All All
Operating System Freebsd Freebsd 14.3 p4 All All
Operating System Freebsd Freebsd 14.3 p5 All All
Operating System Freebsd Freebsd 14.3 p6 All All
Operating System Freebsd Freebsd 14.3 p7 All All
Operating System Freebsd Freebsd 14.3 p8 All All
Operating System Freebsd Freebsd 14.3 p9 All All
Operating System Freebsd Freebsd 14.4 - All All
Operating System Freebsd Freebsd 14.4 p1 All All
Operating System Freebsd Freebsd 14.4 rc1 All All
Operating System Freebsd Freebsd 15.0 - All All
Operating System Freebsd Freebsd 15.0 p1 All All
Operating System Freebsd Freebsd 15.0 p2 All All
Operating System Freebsd Freebsd 15.0 p3 All All
Operating System Freebsd Freebsd 15.0 p4 All All
Operating System Freebsd Freebsd 15.0 p5 All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA FreeBSD FreeBSD affected 15.0-RELEASE p6 release Not specified
CNA FreeBSD FreeBSD affected 14.4-RELEASE p2 release Not specified
CNA FreeBSD FreeBSD affected 14.3-RELEASE p11 release Not specified
CNA FreeBSD FreeBSD affected 13.5-RELEASE p12 release Not specified

References

ReferenceSourceLinkTags
security.freebsd.org/advisories/FreeBSD-SA-26:10.tty.asc [email protected] security.freebsd.org Vendor Advisory
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Nicholas Carlini using Claude, Anthropic (en)

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