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Advisory severityHigh7.3Red Hat Linux

High [CVE-2026-56002] PCF Font Parsing Heap Buffer Overflow

This high-severity Red Hat Linux advisory covers CVE-2026-56002 affecting Red Hat Enterprise Linux 10.0 Extended Update Support, Red Hat Enterprise Linux 7 Extended Lifecycle Support, Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support.

Aggregated and source-linked by VulniPulse. Data sources, validation and limitations.

CVE-2026-56002 Source published Source updated

VulniPulse record published Record updated

CVE-2026-56002
Affected products & platforms
Red Hat LinuxRed Hat Enterprise Linux
Open source advisory

Summary

A heap bufferflow in pcfReadFont() due to missing glyph bounds checking in libXfont2 before 2.0.8 allows attackers authenticated as X client to execute code within the X server. A flaw was found in libXfont2.

A specially crafted PCF (Portable Compiled Format) font file, when processed by libXfont2, can lead to a buffer overflow. This occurs because the font parsing process does not properly validate the size of a bitmap buffer against the glyph metrics provided in the malicious font file.

An attacker could exploit this vulnerability by providing a malicious font, potentially leading to arbitrary code execution or a denial of service. This is an Important flaw in libXfont2, affecting Red Hat Enterprise Linux.

A heap buffer overflow during PCF font file parsing can lead to arbitrary code execution or denial of service. Exploitation requires processing a specially crafted font file, but does not necessitate rendering.

Red Hat severity: Important — CVSS 7.3 (CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H). Weakness: CWE-787.

Affected products named by the advisory: Red Hat Enterprise Linux 10.0 Extended Update Support; Red Hat Enterprise Linux 7 Extended Lifecycle Support; Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support; Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On; and 8 more.

Is CVE-2026-56002 exploited?

No exploitation is reported in the sources VulniPulse tracks: CVE-2026-56002 is not in the CISA KEV catalog (checked ) and this advisory does not report exploitation. That is not proof the vulnerability cannot be exploited.

How do I fix CVE-2026-56002?

Upgrade to a fixed release named by Red Hat:

  • libXfont2-0:2.0.6-5.el10_2.1
  • libXfont2-0:2.0.6-5.el10_0.1
  • libXfont2-0:2.0.3-2.el7_9
  • libXfont2-0:2.0.3-2.el8_10.1
  • libXfont2-0:2.0.3-2.el8_4.1
  • libXfont2-0:2.0.3-2.el8_6.1
  • libXfont2-0:2.0.3-2.el8_8.1
  • libXfont2-0:2.0.3-12.el9_8.1
  • libXfont2-0:2.0.3-12.el9_2.1
  • libXfont2-0:2.0.3-12.el9_4.1
  • libXfont2-0:2.0.3-12.el9_6.1
  • RHSA-2026:47079

10 more fixed releases are listed below.

Confirm against the vendor advisory before you patch.

Affected versions
  • < 2.0.8

Official advisory · high-confidence parse· fetched 10 days ago·verify at source

Fixed versions
  • libXfont2-0:2.0.6-5.el10_2.1
  • libXfont2-0:2.0.6-5.el10_0.1
  • libXfont2-0:2.0.3-2.el7_9
  • libXfont2-0:2.0.3-2.el8_10.1
  • libXfont2-0:2.0.3-2.el8_4.1
  • libXfont2-0:2.0.3-2.el8_6.1
  • libXfont2-0:2.0.3-2.el8_8.1
  • libXfont2-0:2.0.3-12.el9_8.1
  • libXfont2-0:2.0.3-12.el9_2.1
  • libXfont2-0:2.0.3-12.el9_4.1
  • libXfont2-0:2.0.3-12.el9_6.1
  • RHSA-2026:47079
  • RHSA-2026:51061
  • RHSA-2026:51063
  • RHSA-2026:47103
  • RHSA-2026:51060
  • RHSA-2026:51066
  • RHSA-2026:51067
  • RHSA-2026:47084
  • RHSA-2026:51062
  • RHSA-2026:51058
  • RHSA-2026:51059

Official advisory · high-confidence parse· fetched 10 days ago·verify at source

Mitigation

Upgrade to a fixed release: libXfont2-0:2.0.6-5.el10_2.1, libXfont2-0:2.0.6-5.el10_0.1, libXfont2-0:2.0.3-2.el7_9, libXfont2-0:2.0.3-2.el8_10.1, libXfont2-0:2.0.3-2.el8_4.1, libXfont2-0:2.0.3-2.el8_6.1. That is the remediation for this advisory.

The vendor advisory may list interim mitigations or workarounds not captured here. Review it before change work.

Official advisory · high-confidence parse· fetched 10 days ago·verify at source

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