CVE catalog

CVE-2026-44950

libxfont: CVE-2026-44950

Severity: Critical · CVSS 9.5CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/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
Published: Aug 4, 2026, 10:00:00 PM UTC
Source: [NVD] · [CVE record]
EPSS: 0.26% · Oct 22, 2026

fs_read_glyphs() in the libXfont2 font-server client (src/fc/fserve.c) copies each glyph's bitmap into a single buffer. Existing checks validates only that the source slice (position, length) lies within the source bitmap buffer. It does not check whether the running destination cursor has exceeded the allocation. A malicious font server can send overlapping source offsets -- for example 1000 glyphs each referencing {position:0, length:64} with nbytes=64. Each individual source range passes the existing validation, but the cumulative writes total 64000 bytes into a 64-byte destination buffer. This is a heap buffer overflow with attacker-controlled content.

Vulnerable and fixed packages

Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.

Distribution	Package	Release	Version	Status
Debian	libxfont	sid	`1:2.0.9-1`	fixed
Debian	libxfont	forky	`1:2.0.9-1`	fixed
Debian	libxfont	trixie	`1:2.0.6-1+deb13u1`	vulnerable
Debian	libxfont	trixie-security	`1:2.0.6-1+deb13u1`	vulnerable
Debian	libxfont	bookworm	`1:2.0.6-1`	vulnerable
Debian	libxfont	bookworm-security	`1:2.0.6-1+deb12u1`	vulnerable
Ubuntu	libxfont2	16.04	`1:2.0.1-3~ubuntu16.04.1`	vulnerable
Ubuntu	libxfont2	16.04	`1:2.0.1-3~ubuntu16.04.2`	vulnerable
Ubuntu	libxfont2	16.04	`1:2.0.1-3~ubuntu16.04.3`	vulnerable
Suse	libXfont2	linux enterprise server 16.0	`2.0.7-160000.5.1`	fixed
Suse	libXfont2	linux enterprise server for sap applications 16.0	`2.0.7-160000.5.1`	fixed
Suse	libXfont2	linux enterprise server 16.0	`2.0.7-160000.5.1`	fixed
Suse	libXfont2	linux enterprise server for sap applications 16.0	`2.0.7-160000.5.1`	fixed
Opensuse	libXfont2	leap 16.0	`2.0.7-160000.5.1`	fixed
Opensuse	libXfont2	tumbleweed	`2.0.7-3.1`	fixed
Suse	libXfont2	linux enterprise server 12 sp5-ltss	`2.0.3-3.6.1`	fixed
Suse	libXfont2	linux enterprise server ltss extended security 12 sp5	`2.0.3-3.6.1`	fixed
Suse	libXfont2	linux enterprise module for basesystem 15 sp7	`2.0.3-150000.3.6.1`	fixed
Suse	libXfont2	linux enterprise high performance computing 15 sp4-espos	`2.0.3-150000.3.6.1`	fixed
Suse	libXfont2	linux enterprise high performance computing 15 sp4-ltss	`2.0.3-150000.3.6.1`	fixed
Suse	libXfont2	linux enterprise high performance computing 15 sp5-espos	`2.0.3-150000.3.6.1`	fixed
Suse	libXfont2	linux enterprise high performance computing 15 sp5-ltss	`2.0.3-150000.3.6.1`	fixed
Suse	libXfont2	linux enterprise server 15 sp4-ltss	`2.0.3-150000.3.6.1`	fixed
Suse	libXfont2	linux enterprise server 15 sp5-ltss	`2.0.3-150000.3.6.1`	fixed
Suse	libXfont2	linux enterprise server 15 sp6-ltss	`2.0.3-150000.3.6.1`	fixed
Suse	libXfont2	linux enterprise server for sap applications 15 sp4	`2.0.3-150000.3.6.1`	fixed
Suse	libXfont2	linux enterprise server for sap applications 15 sp5	`2.0.3-150000.3.6.1`	fixed
Suse	libXfont2	linux enterprise server for sap applications 15 sp6	`2.0.3-150000.3.6.1`	fixed

Fixed-version evidence

Distribution	Package	Type	Release	Fixed version	Urgency	Origin	Bugs
Debian	libxfont	source	sid	`1:2.0.9-1`	unimportant	Not reported	Not reported
Debian	libxfont	source	forky	`1:2.0.9-1`	unimportant	Not reported	Not reported
Debian	libxfont	source	trixie	`(unfixed)`	unimportant	Not reported	Not reported
Debian	libxfont	source	bookworm	`(unfixed)`	unimportant	Not reported	Not reported
Suse	libXfont2	rpm	linux enterprise server 16.0	`2.0.7-160000.5.1`	Not reported	SUSE-SU-2026:23151-1	Not reported
Suse	libXfont2	rpm	linux enterprise server for sap applications 16.0	`2.0.7-160000.5.1`	Not reported	SUSE-SU-2026:23151-1	Not reported
Suse	libXfont2	rpm	linux enterprise server 16.0	`2.0.7-160000.5.1`	Not reported	SUSE-SU-2026:23128-1	Not reported
Suse	libXfont2	rpm	linux enterprise server for sap applications 16.0	`2.0.7-160000.5.1`	Not reported	SUSE-SU-2026:23128-1	Not reported
Opensuse	libXfont2	rpm	leap 16.0	`2.0.7-160000.5.1`	Not reported	OPENSUSE-SU-2026:21539-1	Not reported
Opensuse	libXfont2	rpm	tumbleweed	`2.0.7-3.1`	Not reported	OPENSUSE-SU-2026:11463-1	Not reported
Suse	libXfont2	rpm	linux enterprise server 12 sp5-ltss	`2.0.3-3.6.1`	Not reported	SUSE-SU-2026:3499-1	Not reported
Suse	libXfont2	rpm	linux enterprise server ltss extended security 12 sp5	`2.0.3-3.6.1`	Not reported	SUSE-SU-2026:3499-1	Not reported
Suse	libXfont2	rpm	linux enterprise module for basesystem 15 sp7	`2.0.3-150000.3.6.1`	Not reported	SUSE-SU-2026:3500-1	Not reported
Suse	libXfont2	rpm	linux enterprise high performance computing 15 sp4-espos	`2.0.3-150000.3.6.1`	Not reported	SUSE-SU-2026:3500-1	Not reported
Suse	libXfont2	rpm	linux enterprise high performance computing 15 sp4-ltss	`2.0.3-150000.3.6.1`	Not reported	SUSE-SU-2026:3500-1	Not reported
Suse	libXfont2	rpm	linux enterprise high performance computing 15 sp5-espos	`2.0.3-150000.3.6.1`	Not reported	SUSE-SU-2026:3500-1	Not reported
Suse	libXfont2	rpm	linux enterprise high performance computing 15 sp5-ltss	`2.0.3-150000.3.6.1`	Not reported	SUSE-SU-2026:3500-1	Not reported
Suse	libXfont2	rpm	linux enterprise server 15 sp4-ltss	`2.0.3-150000.3.6.1`	Not reported	SUSE-SU-2026:3500-1	Not reported
Suse	libXfont2	rpm	linux enterprise server 15 sp5-ltss	`2.0.3-150000.3.6.1`	Not reported	SUSE-SU-2026:3500-1	Not reported
Suse	libXfont2	rpm	linux enterprise server 15 sp6-ltss	`2.0.3-150000.3.6.1`	Not reported	SUSE-SU-2026:3500-1	Not reported
Suse	libXfont2	rpm	linux enterprise server for sap applications 15 sp4	`2.0.3-150000.3.6.1`	Not reported	SUSE-SU-2026:3500-1	Not reported
Suse	libXfont2	rpm	linux enterprise server for sap applications 15 sp5	`2.0.3-150000.3.6.1`	Not reported	SUSE-SU-2026:3500-1	Not reported
Suse	libXfont2	rpm	linux enterprise server for sap applications 15 sp6	`2.0.3-150000.3.6.1`	Not reported	SUSE-SU-2026:3500-1	Not reported

OpenFactory catalog packages

[Debian 12 (Bookworm)]

[libxfont2]Affected
Source package: [libxfont]
Details (4)
- 1:2.0.6-1 · amd64 · bookworm
  Affected
  dsa · libxfont · debian · bookworm; dsa · libxfont · debian · 12
- 1:2.0.6-1 · arm64 · bookworm
  Affected
  dsa · libxfont · debian · bookworm; dsa · libxfont · debian · 12
- 1:2.0.6-1+deb12u1 · amd64 · bookworm-security
  Affected
  dsa · libxfont · debian · bookworm; dsa · libxfont · debian · 12
- 1:2.0.6-1+deb12u1 · arm64 · bookworm-security
  Affected
  dsa · libxfont · debian · bookworm; dsa · libxfont · debian · 12
[libxfont-dev]Affected
Source package: [libxfont]
Details (4)
- 1:2.0.6-1 · amd64 · bookworm
  Affected
  dsa · libxfont · debian · bookworm; dsa · libxfont · debian · 12
- 1:2.0.6-1 · arm64 · bookworm
  Affected
  dsa · libxfont · debian · bookworm; dsa · libxfont · debian · 12
- 1:2.0.6-1+deb12u1 · amd64 · bookworm-security
  Affected
  dsa · libxfont · debian · bookworm; dsa · libxfont · debian · 12
- 1:2.0.6-1+deb12u1 · arm64 · bookworm-security
  Affected
  dsa · libxfont · debian · bookworm; dsa · libxfont · debian · 12

[Debian 13 (Trixie)]

[libxfont2]Affected
Source package: [libxfont]
Details (4)
- 1:2.0.6-1+b3 · amd64 · trixie
  Affected
  dsa · libxfont · debian · 13
- 1:2.0.6-1+b3 · arm64 · trixie
  Affected
  dsa · libxfont · debian · 13
- 1:2.0.6-1+deb13u1 · amd64 · trixie-security
  Affected
  dsa · libxfont · debian · 13
- 1:2.0.6-1+deb13u1 · arm64 · trixie-security
  Affected
  dsa · libxfont · debian · 13
[libxfont-dev]Affected
Source package: [libxfont]
Details (4)
- 1:2.0.6-1+b3 · amd64 · trixie
  Affected
  dsa · libxfont · debian · 13
- 1:2.0.6-1+b3 · arm64 · trixie
  Affected
  dsa · libxfont · debian · 13
- 1:2.0.6-1+deb13u1 · amd64 · trixie-security
  Affected
  dsa · libxfont · debian · 13
- 1:2.0.6-1+deb13u1 · arm64 · trixie-security
  Affected
  dsa · libxfont · debian · 13

[openSUSE Tumbleweed]

[libXfont2-2]Unknown
Source package: [libXfont2]
Details (1)
- 2.0.7-3.1 · x86_64 · tumbleweed
  Unknown · Fixed: 2.0.7-3.1
  Version impact unknown
  dsa · libXfont2 · opensuse · tumbleweed
[libXfont2-2-32bit]Unknown
Source package: [libXfont2]
Details (1)
- 2.0.7-3.1 · x86_64 · tumbleweed
  Unknown · Fixed: 2.0.7-3.1
  Version impact unknown
  dsa · libXfont2 · opensuse · tumbleweed
[libXfont2-devel]Unknown
Source package: [libXfont2]
Details (1)
- 2.0.7-3.1 · x86_64 · tumbleweed
  Unknown · Fixed: 2.0.7-3.1
  Version impact unknown
  dsa · libXfont2 · opensuse · tumbleweed
[libXfont2-devel-32bit]Unknown
Source package: [libXfont2]
Details (1)
- 2.0.7-3.1 · x86_64 · tumbleweed
  Unknown · Fixed: 2.0.7-3.1
  Version impact unknown
  dsa · libXfont2 · opensuse · tumbleweed

Observed: Oct 24, 2026, 4:27:23 AM UTC

References

[CERT-Bund public advisories] · [Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX]