CVE-2026-56003

highCVSS 8.5covered by 2 sourcesfirst seen 2026-07-02

A heap buffer overflow due to missing size checking in the property buffer when parsing PCF files in libXfont2 ComputeScaledProperties() before libXfont2 before 2.0.8 could be used by attackers using authenticated X clients to execute code within the X server.

CSIRTS triage

What: A buffer heap overflow vulnerability exists in the computeProps property.
Who is affected: Users of libXfont2 are affected.
Urgency: High urgency for remediation due to the severity of the vulnerability.
Action: Update libXfont2 to the latest version to mitigate this vulnerability.

AI-assisted analysis generated from the source advisory — verify against the original.

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Exploitation outlook

Low exploitation risk0.64% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 47% of all EPSS-scored CVEs.

Advisory coverage (2)

highCVE-2026-56003: A heap buffer overflow due to missing size checking in the property buffer when parsing PCF fi…nvd · 2026-07-08
highCVE-2026-56003: libXfont2 computeProps Property Buffer Heap Buffer Overflowmsrc · 2026-07-02

External references

NVD record for CVE-2026-56003

CVE.org record

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