What is CVE-2026-56002?

CVE-2026-56002 is a high-severity vulnerability in X Libxfont, classified under Heap-based Buffer Overflow. CVSS score: 8.5/10. Published 2026-07-08.

How severe is CVE-2026-56002?

High severity. CVSS v3 base score is 8.5 out of 10.

Buffer overflow in X Libxfont

CVE-2026-56002

A heap bufferflow in pcfReadFont() due to missing glyph bounds checking in libXfont2 before 2.0.8 allows attackers authenticated as X client to execute code within the X server.

Vulnerability class: Buffer Overflow

Published 2026-07-08 · last modified 2026-07-13.

CVSS v3 metric

CVSS v3 base score 8.5 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.006 (44.9th percentile), scored 2026-10-07.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 45th percentile — 44.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.004 · newest: 0.006 · change: +0.001

Affected products

X Libxfont
X.org Libxfont2 — versions 0

Weakness classification (CWE)

CWE-122 — Heap-based Buffer Overflow

References

gitlab.freedesktop.org/xorg/lib/libxfont/-/commit/b4389e0b1d84a690b819bb27b1439… (Patch, patch)
www.openwall.com/lists/oss-security/2026/07/08/1 (vendor-advisory, Patch, Mailing List, Third Party Advisory)

Frequently asked questions

What is CVE-2026-56002?: CVE-2026-56002 is a high-severity vulnerability in X Libxfont, classified under Heap-based Buffer Overflow. CVSS score: 8.5/10. Published 2026-07-08.
How severe is CVE-2026-56002?: High severity. CVSS v3 base score is 8.5 out of 10.