What is CVE-2026-56001?

CVE-2026-56001 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-2026-56001?

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

Buffer overflow in X Libxfont

CVE-2026-56001

A heap buffer overflow in BitmapScaleBitmaps in libXfont2 before 2.0.8 due to an overflowing 32bit size could be used by attackers able to access the X Server to execute code within the X server cont

Vulnerability class: Buffer Overflow

Published 2026-07-08 · last modified 2026-07-09.

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 (47.8th percentile), scored 2026-10-07.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 48th percentile — 47.8% 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: +0.002

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/be0b08e2d354138d3222b4490e2a7… (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-2026-56001?: CVE-2026-56001 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-2026-56001?: High severity. CVSS v3 base score is 8.5 out of 10.