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Fencer Vulns
high 8.5

CVE-2026-56003 json

libXfont2 computeProps Property Buffer Heap Buffer Overflow

published 2026-07-08 4 mo ago modified 2026-10-25 14 d ago also EUVD-2026-42212

cvss
8.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 34%
public exploits
0
none known

Summary

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.

Patch / fix

  • X.Org libXfont2 2.0.8
  • libxfont Debian 12 1:2.0.6-1+deb12u1
  • libxfont Debian 13 1:2.0.6-1+deb13u1
  • libxfont Debian 14 1:2.0.8-1

debian advisories DEBIAN-CVE-2026-56003

  • libxfont Ubuntu 22.04 LTS 1:2.0.5-1ubuntu0.2
  • libxfont Ubuntu 24.04 LTS 1:2.0.6-1+deb13u1build0.24.04.2
  • libxfont Ubuntu 26.04 LTS 1:2.0.6-2ubuntu0.2
  • libxfont Ubuntu Pro 14.04 LTS 1:1.4.7-1ubuntu0.4+esm2
  • libxfont Ubuntu Pro 16.04 LTS 1:1.5.1-1ubuntu0.16.04.4+esm2
  • libxfont Ubuntu Pro 18.04 LTS 1:2.0.3-1ubuntu0.1~esm2
  • libxfont Ubuntu Pro 20.04 LTS 1:2.0.3-1ubuntu0.20.04.1~esm2

ubuntu advisories UBUNTU-CVE-2026-56003

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • libXfont2 RHEL 9 2.0.3-12.el9_8.1
  • libXfont2 RHEL 8 2.0.3-2.el8_10.1
  • libXfont2 RHEL 10.2 2.0.6-5.el10_2.1
  • libXfont2 RHEL 8.6 EUS_LONG_LIFE, RHEL 8.6 AUS 2.0.3-2.el8_6.1
  • libXfont2 RHEL 8.8 TUS, RHEL 8.8 E4S 2.0.3-2.el8_8.1
  • libXfont2 RHEL 9.2 E4S 2.0.3-12.el9_2.1
  • libXfont2 RHEL 7 ELS 2.0.3-2.el7_9
  • libXfont2 RHEL 8.4 EUS_LONG_LIFE, RHEL 8.4 AUS 2.0.3-2.el8_4.1

red hat advisories RHSA-2026:51066RHSA-2026:51067RHSA-2026:51062RHSA-2026:51063RHSA-2026:51060RHSA-2026:51061

  • libXfont2 SLES for SAP applications 16.0, SLES 16.0 2.0.7-160000.4.1
  • libXfont2 SLES for SAP 15 SP6, SLES for SAP 15 SP5, SLES for SAP 15 SP4 +8 more 2.0.3-150000.3.3.1
  • libXfont2 SLES 12 SP5-LTSS 2.0.3-3.3.1

suse advisories SUSE-SU-2026:22614-1SUSE-SU-2026:2794-1SUSE-SU-2026:2793-1

  • libXfont2 openSUSE Leap 16.0 2.0.7-160000.4.1
  • libXfont2 openSUSE Tumbleweed 2.0.7-2.1

opensuse advisories openSUSE-SU-2026:21284-1openSUSE-SU-2026:11233-1

  • libXfont2 AlmaLinux 10 2.0.6-5.el10_2.1
  • libXfont2 AlmaLinux 9 2.0.3-12.el9_8.1
  • libXfont2 AlmaLinux 8 2.0.3-2.el8_10.1

almalinux advisories ALSA-2026:47079ALSA-2026:47084ALSA-2026:47103

  • libXfont2 Rocky Linux 8 2.0.3-2.el8_10.1

rocky linux advisories RLSA-2026:47103

  • libxfont2 Alpine 3.24 2.0.8-r0

alpine advisories ALPINE-CVE-2026-56003

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • libXfont2 Azure Linux 3.0 2.0.8-1

azure linux advisories AZL-92084

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-56003 updated cvss 8.8

libXfont2: libXfont2: arbitrary code execution via heap buffer overflow in ComputeScaledProperties

  • Red Hat CodeReady Linux Builder EUS (v.9.6) libXfont2-devel 2.0.3-12.el9_6.1, libXfont2-debuginfo 2.0.3-12.el9_6.1, libXfont2-debugsource 2.0.3-12.el9_6.1
    fixed: vendor fix RHSA-2026:51059
  • Red Hat Enterprise Linux AppStream (v. 8) libXfont2 2.0.3-2.el8_10.1
    fixed: vendor fix RHSA-2026:47103
  • Red Hat Enterprise Linux AppStream (v. 9) libXfont2 2.0.3-12.el9_8.1
    fixed: vendor fix RHSA-2026:47084
  • Red Hat Enterprise Linux AppStream (v. 10) libXfont2 2.0.6-5.el10_2.1
    fixed: vendor fix RHSA-2026:47079
  • Red Hat Enterprise Linux AppStream AUS (v.8.4) libXfont2 2.0.3-2.el8_4.1
    fixed: vendor fix RHSA-2026:51060
  • Red Hat Enterprise Linux AppStream AUS (v.8.6) libXfont2 2.0.3-2.el8_6.1
    fixed: vendor fix RHSA-2026:51066
  • Red Hat Enterprise Linux AppStream E4S (v.8.8) libXfont2 2.0.3-2.el8_8.1
    fixed: vendor fix RHSA-2026:51067
  • Red Hat Enterprise Linux AppStream E4S (v.9.2) libXfont2 2.0.3-12.el9_2.1
    fixed: vendor fix RHSA-2026:51062
show 11 more
  • Red Hat Enterprise Linux AppStream E4S (v.9.4) libXfont2 2.0.3-12.el9_4.1
    fixed: vendor fix RHSA-2026:51058
  • Red Hat Enterprise Linux AppStream EUS (v. 10.0) libXfont2 2.0.6-5.el10_0.1
    fixed: vendor fix RHSA-2026:51061
  • Red Hat Enterprise Linux AppStream EUS (v.9.6) libXfont2 2.0.3-12.el9_6.1
    fixed: vendor fix RHSA-2026:51059
  • Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4) libXfont2 2.0.3-2.el8_4.1
    fixed: vendor fix RHSA-2026:51060
  • Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.6) libXfont2 2.0.3-2.el8_6.1
    fixed: vendor fix RHSA-2026:51066
  • Red Hat Enterprise Linux AppStream TUS (v.8.8) libXfont2 2.0.3-2.el8_8.1
    fixed: vendor fix RHSA-2026:51067
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) libXfont2-devel 2.0.3-12.el9_8.1, libXfont2-debuginfo 2.0.3-12.el9_8.1, libXfont2-debugsource 2.0.3-12.el9_8.1
    fixed: vendor fix RHSA-2026:47084
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) libXfont2-devel 2.0.6-5.el10_2.1, libXfont2-debuginfo 2.0.6-5.el10_2.1, libXfont2-debugsource 2.0.6-5.el10_2.1
    fixed: vendor fix RHSA-2026:47079
  • Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0) libXfont2-devel 2.0.6-5.el10_0.1, libXfont2-debuginfo 2.0.6-5.el10_0.1, libXfont2-debugsource 2.0.6-5.el10_0.1
    fixed: vendor fix RHSA-2026:51061
  • Red Hat Enterprise Linux CRB (v. 8) libXfont2-devel 2.0.3-2.el8_10.1, libXfont2-debuginfo 2.0.3-2.el8_10.1, libXfont2-debugsource 2.0.3-2.el8_10.1
    fixed: vendor fix RHSA-2026:47103
  • Red Hat Enterprise Linux Server (v. 7 ELS) libXfont2 2.0.3-2.el7_9 Red Hat Enterprise Linux Server Optional (v. 7 ELS) libXfont2-devel 2.0.3-2.el7_9, libXfont2-debuginfo 2.0.3-2.el7_9
    fixed: vendor fix RHSA-2026:51063

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
4 mo ago

Exploit prediction

0.40% chance of exploitation in the next 30 days, higher than 34% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 8.5 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
NVD 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

  • X.Org libXfont2

Classification

Weakness
  • CWE-122 Heap-based Buffer Overflow

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.