Microsoft security update for CVE-2026-59679 — azl3 libXfont2 2.0.8-1 on Azure Linux 3.0
🔗 CVE IDs covered (1)
📋 Microsoft's advisory
EchelonGraph does not copy Microsoft's advisory page: its FAQ and remediation text are not shown here. Read the advisory on https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-59679. This page also shows what EchelonGraph holds for CVE-2026-59679, with the description from its CVE record, which the CVE Numbering Authority that assigned the CVE wrote: for a CVE Microsoft assigned, often in the words of Microsoft's own advisory.
🎯 Affected products1
- azl3 libXfont2 2.0.8-1 on Azure Linux 3.0
✅ Updates Microsoft lists: 1 update
1 row: one per KB article or update, update type and fixed build. Their details are on Microsoft's advisory.
| KB article | Update | Fixed build |
|---|---|---|
| — | Security Update | 2.0.9-1 |
🧭 EchelonGraph on CVE-2026-59679
- EchelonGraph score
- 9.0 CRITICAL
- CISA KEV
- Not listed
- Fix status
- A fix is available — apply it.
Description from the CVE record (CVE.org), as published by its numbering authority
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.
Published by SUSE, the CVE Numbering Authority that assigned CVE-2026-59679, in its CVE record at CVE.org; reused under the CVE Program's Terms of Use (its licence and MITRE's copyright notice are in our Terms of Service).