Use After Free in Tigervnc

CVE-2025-26601

A use-after-free flaw was found in X.Org and Xwayland. When changing an alarm, the values of the change mask are evaluated one after the other, changing the trigger values as requested, and eventually, SyncInitTrigger() is called. If one o…

Vulnerability class: Use-After-Free

EPSS: 0.004 (28.2th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2025-26601?
CVE-2025-26601 is a high-severity vulnerability in Tigervnc, classified under Use After Free. CVSS score: 7.8/10. Published 2025-02-25.
How severe is CVE-2025-26601?
High severity. CVSS v3 base score is 7.8 out of 10.
Is CVE-2025-26601 known to be exploited?
2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.