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Vulnerability record · CVE-2026-56003 · published 8 July 2026

CVE-2026-56003: Libxfont heap-based buffer overflow vulnerability

XX · Libxfont

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.

8.8 CVSS 3.1 High EPSS 0.62% · top 52.6% CWE-122 · Heap-based buffer overflow
8.8CVSS 3.1 base score
0.62%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
2References
9 Jul 2026Last modified by NVD

Description

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.

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://gitlab.freedesktop.org/xorg/lib/libxfont/-/commit/dff957a5158da038a282a59a31fe736702732939 Patch
https://www.openwall.com/lists/oss-security/2026/07/08/1 Mailing ListPatchThird Party Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.8CVE-2007-5199Libxfont memory buffer overflow vulnerabilityA single byte overflow in catalogue.c in X.Org libXfont 1.3.1 allows remote attackers to have unspecified impact.EPSS 2.2%9.3CVE-2013-6462Libxfont memory buffer overflow vulnerabilityStack-based buffer overflow in the bdfReadCharacters function in bitmap/bdfread.c in X.Org libXfont 1.1 through 1.4.6 allows remote attackers to caus…EPSS 10%9.3CVE-2011-2895Freetype memory buffer overflow vulnerabilityThe LZW decompressor in (1) the BufCompressedFill function in fontfile/decompress.c in X.Org libXfont before 1.4.4 and (2) compress/compress.c in 4.3…EPSS 8.4%8.8CVE-2026-56002Libxfont heap-based buffer overflow vulnerabilityA heap bufferflow in pcfReadFont() due to missing glyph bounds checking in libXfont2 before 2.0.8  allows attackers authenticated as X client to exec…EPSS 0.56%8.8CVE-2026-56001Libxfont heap-based buffer overflow vulnerabilityA 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…EPSS 0.62%8.5CVE-2015-1804Libxfont vulnerabilityThe bdfReadCharacters function in bitmap/bdfread.c in X.Org libXfont before 1.4.9 and 1.5.x before 1.5.1 does not properly perform type conversion fo…EPSS 5.0%8.5CVE-2015-1803Canonical ubuntu linux vulnerabilityThe bdfReadCharacters function in bitmap/bdfread.c in X.Org libXfont before 1.4.9 and 1.5.x before 1.5.1 does not properly handle character bitmaps i…EPSS 4.9%8.5CVE-2015-1802Libxfont memory buffer overflow vulnerabilityThe bdfReadProperties function in bitmap/bdfread.c in X.Org libXfont before 1.4.9 and 1.5.x before 1.5.1 allows remote authenticated users to cause a…EPSS 4.9%

Source: NIST National Vulnerability Database (record CVE-2026-56003), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.