DEBIAN-CVE-2026-59679
- Source
- https://security-tracker.debian.org/tracker/CVE-2026-59679
- Import Source
- https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-59679.json
- JSON Data
- https://api.osv.dev/v1/vulns/DEBIAN-CVE-2026-59679
- Upstream
- Published
- 2026-09-10T09:17:02Z
- Modified
- 2026-09-11T06:00:09Z
- Severity
-
- 9.2 (Critical) CVSS_V4 - CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X CVSS Calculator
- Summary
- [none]
- Details
-
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.
- References
Affected packages
Debian:12 / libxfont
Package
- Name
- libxfont
- Purl
- pkg:deb/debian/libxfont?arch=source&distro=bookworm
Debian:13 / libxfont
Package
- Name
- libxfont
- Purl
- pkg:deb/debian/libxfont?arch=source&distro=trixie
Debian:14 / libxfont
Package
- Name
- libxfont
- Purl
- pkg:deb/debian/libxfont?arch=source&distro=forky