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CVE-2025-26601

high

A use-after-free flaw was found in X.Org and Xwayland.

Vendor / product: Tigervnc — tigervnc

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 of the changes triggers an error, the function will return early, not adding the new sync object, possibly causing a use-after-free when the alarm eventually triggers.

CVSS
7.8
7.8 (CVSS v3.1)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Severity source: NVD CVSS v3.1 (nvd@nist.gov)
Timeline (UTC)
Published: 2025-02-25 16:15
Modified: 2026-11-04 22:17
NVD status: Modified
Last synced 3 hours ago
Verified against the source API 2026-11-04 22:37 UTC
Exploitation
Not listed in CISA KEV (as of last catalog sync)
Absence from KEV does not mean a CVE is not exploited. Exploitation status: unknown (no authoritative evidence in our sources).

Affected products

tigervnc / tigervnc all versions
x.org / x_server <21.1.16
x.org / xwayland <24.1.6
redhat / enterprise_linux 7.0, 8.0, 9.0

Weakness classification (CWE)

CWE-416

Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.

Mitigation & advisories

No vendor advisory or patch reference tagged by NVD. Check the references below.

References

Data sources

NVD CVE API 2.0 — fetched 2026-11-04 22:37 UTC · record ↗

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