CVE-2026-5398 - Vulnerability Details - OpenCVE

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.

No CVSS v4.0

Attack Vector Local

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

The EPSS score is 0.00018.

Exploitation none

Automatable no

Technical Impact total

Vendors	Products
Freebsd	Freebsd

No data.

No data.

OpenCVE Enrichment is a feature of OpenCVE that uses AI to automatically link vendors and products to CVEs. Learn more on GitHub.

Vendors	Products
Freebsd	Freebsd

References

Link	Providers
https://security.freebsd.org/advisories/FreeBSD-SA-26:10.tty.asc

History

Wed, 22 Apr 2026 15:15:00 +0000

Type	Values Removed	Values Added
Metrics		cvssV3_1 `{'score': 8.4, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'}` ssvc `{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}`

Wed, 22 Apr 2026 03:45:00 +0000

Type	Values Removed	Values Added
First Time appeared		Freebsd Freebsd freebsd
Vendors & Products		Freebsd Freebsd freebsd

Wed, 22 Apr 2026 02:45:00 +0000

Type	Values Removed	Values Added
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.
Title		Kernel use-after-free bug in the TIOCNOTTY handler
Weaknesses		CWE-416
References		https://security.freebsd.org/advisories/FreeBSD-SA-26:10.tty.asc

MITRE

Status: PUBLISHED

Assigner: freebsd

Published: 2026-04-22T02:23:56.767Z

Updated: 2026-04-22T14:24:21.661Z

Reserved: 2026-04-02T01:48:17.131Z

Link: CVE-2026-5398

Vulnrichment

Updated: 2026-04-22T14:24:12.587Z

NVD

Status : Received

Published: 2026-04-22T03:16:01.213

Modified: 2026-04-22T15:16:17.050

Link: CVE-2026-5398

Redhat

No data.

OpenCVE Enrichment

Updated: 2026-04-22T04:30:05Z

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{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "[15.0-RELEASE,p6)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "[14.4-RELEASE,p2)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "[14.3-RELEASE,p11)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "[13.5-RELEASE,p12)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "FreeBSD", "source": "cna", "vendor": "FreeBSD"}, "product": "freebsd", "vendor": "freebsd"}], "analysis": {"en": {"generated_at": "2026-04-22T04:20:57.396328+00:00", "value": {"mitigation_remediation": ["Apply the latest FreeBSD security updates that contain the TIOCNOTTY patch.", "Restrict use of the TIOCNOTTY ioctl to privileged users only and disable it for untrusted processes.", "Monitor for abnormal privilege\u2011escalation attempts and audit system processes that gain root privileges."], "summary": {"action": "Immediate Patch", "impact": "Root privilege escalation"}, "threat_synthesis": {"affected_systems": "FreeBSD is the affected vendor. No specific product release or version information is listed in the advisory; the vulnerability applies to all affected FreeBSD releases for which the TIOCNOTTY handler implementation is unpatched.", "description_and_impact": "A use\u2011after\u2011free condition in the FreeBSD TIOCNOTTY handler allows a process that has cleared its controlling terminal to later access a dangling pointer in the terminal structure after the process exits. An attacker can use the freed reference to elevate privileges and gain root access.", "risk_and_exploitability": "The CVSS score is not provided, and EPSS is unavailable, but the vulnerability is known to allow local processes to gain root credentials. Since the attack requires the attacker to invoke the TIOCNOTTY ioctl on a controlling terminal, the likely vector is local access. The CVE is not listed in the CISA KEV catalog, yet it remains a critical privilege\u2011escalation flaw."}}}}, "created": "2026-04-22T03:30:06.536006+00:00", "updated": "2026-04-22T04:30:05.297344+00:00", "vendors": ["freebsd", "freebsd$PRODUCT$freebsd"]}