How severe is CVE-2026-5398?

CVE-2026-5398 has a CVSS 3.x base score of 8.4, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-5398 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (6th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-5398?

CVE-2026-5398 primarily affects Freebsd. In total, 33 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2026-5398?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-5398 have an EU (EUVD) identifier?

Yes. CVE-2026-5398 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-24589.

When was CVE-2026-5398 published?

CVE-2026-5398 was published on 2026-04-22 and last updated on 2026-06-17.

CVE-2026-5398

CVE-2026-5398 is a high-severity vulnerability in Freebsd with a CVSS 3.x base score of 8.4. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-416.

Key facts

Severity: High (CVSS 3.x base score 8.4)
EPSS exploit prediction: 0% (6th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-24589
Weakness: CWE-416
Affected product: Freebsd
Published: 2026-04-22
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2026-5398?: 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.
How severe is CVE-2026-5398?: CVE-2026-5398 has a CVSS 3.x base score of 8.4, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-5398 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (6th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-5398?: CVE-2026-5398 primarily affects Freebsd. In total, 33 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-5398?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-5398 have an EU (EUVD) identifier?: Yes. CVE-2026-5398 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-24589.
When was CVE-2026-5398 published?: CVE-2026-5398 was published on 2026-04-22 and last updated on 2026-06-17.

References

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

Affected products (33)

cpe:2.3:o:freebsd:freebsd:13.5:-:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:13.5:beta3:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:13.5:p1:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:13.5:p10:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:13.5:p11:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:13.5:p2:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:13.5:p3:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:13.5:p4:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:13.5:p5:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:13.5:p6:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:13.5:p7:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:13.5:p8:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:13.5:p9:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:14.3:-:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:14.3:p1:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:14.3:p10:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:14.3:p2:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:14.3:p3:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:14.3:p4:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:14.3:p5:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:14.3:p6:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:14.3:p7:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:14.3:p8:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:14.3:p9:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:14.4:-:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:14.4:p1:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:14.4:rc1:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:15.0:-:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:15.0:p1:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:15.0:p2:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:15.0:p3:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:15.0:p4:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:15.0:p5:*:*:*:*:*:*

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