CVE-2026-59679 Affecting libXfont2-devel package, versions <0:2.0.6-5.el10_2.3


Severity

Recommended
high

Based on Rocky Linux security rating.

Threat Intelligence

EPSS
0.26% (17th percentile)

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  • Snyk IDSNYK-ROCKY10-LIBXFONT2DEVEL-18903945
  • published18 Aug 2026
  • disclosed10 Sept 2026

Introduced: 18 Aug 2026

CVE-2026-59679  (opens in a new tab)

How to fix?

Upgrade Rocky-Linux:10 libXfont2-devel to version 0:2.0.6-5.el10_2.3 or higher.
This issue was patched in RLSA-2026:55448.

NVD Description

Note: Versions mentioned in the description apply only to the upstream libXfont2-devel package and not the libXfont2-devel package as distributed by Rocky-Linux. See How to fix? for Rocky-Linux:10 relevant fixed versions and status.

fs_read_glyphs() in the libXfont2 font-server client (src/fc/fserve.c) indexes the per-character encoding[] array using num_chars from the FS_QueryXBitmaps16 reply, but that array was allocated with a size derived from num_extents in the separate FS_QueryXExtents16 reply. The two CARD32 fields are never cross-checked. A malicious or compromised font server can send a small num_extents (e.g. 1) in the extents reply, then a large num_chars (e.g. 100000) in the bitmaps reply. This causes attacker-controlled out-of-bounds heap read and writes.

CVSS Base Scores

version 3.1