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CVE-2025-26596

high

A heap overflow flaw was found in X.Org and Xwayland.

Vendor / product: Tigervnc — tigervnc

A heap overflow flaw was found in X.Org and Xwayland. The computation of the length in XkbSizeKeySyms() differs from what is written in XkbWriteKeySyms(), which may lead to a heap-based buffer overflow.

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 2 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-787

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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Related CVEs

CVE-2025-26601CVE-2025-26600CVE-2025-26599CVE-2025-26598CVE-2025-26597