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 Enterprise Linux 10 2026-07-28T00:00:00Z RHSA-2026:47079 libXfont2-0:2.0.6-5.el10_2.1 Red Hat Enterprise Linux 10.0 Extended Update Support 2026-08-06T00:00:00Z RHSA-2026:51061 libXfont2-0:2.0.6-5.el10_0.1 Red Hat Enterprise Linux 7 Extended Lifecycle Support 2026-08-06T00:00:00Z RHSA-2026:51063 libXfont2-0:2.0.3-2.el7_9 Red Hat Enterprise Linux 8 2026-07-28T00:00:00Z RHSA-2026:47103 libXfont2-0:2.0.3-2.el8_10.1 Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support 2026-08-06T00:00:00Z RHSA-2026:51060 libXfont2-0:2.0.3-2.el8_4.1 Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On 2026-08-06T00:00:00Z RHSA-2026:51060 libXfont2-0:2.0.3-2.el8_4.1 Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support 2026-08-06T00:00:00Z RHSA-2026:51066 libXfont2-0:2.0.3-2.el8_6.1 Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On 2026-08-06T00:00:00Z RHSA-2026:51066 libXfont2-0:2.0.3-2.el8_6.1 Red Hat Enterprise Linux 8.8 Telecommunications Update Service 2026-08-06T00:00:00Z RHSA-2026:51067 libXfont2-0:2.0.3-2.el8_8.1 Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions 2026-08-06T00:00:00Z RHSA-2026:51067 libXfont2-0:2.0.3-2.el8_8.1 Red Hat Enterprise Linux 9 2026-08-03T00:00:00Z RHSA-2026:47084 libXfont2-0:2.0.3-12.el9_8.1 Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions 2026-08-06T00:00:00Z RHSA-2026:51062 libXfont2-0:2.0.3-12.el9_2.1 Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions 2026-08-06T00:00:00Z RHSA-2026:51058 libXfont2-0:2.0.3-12.el9_4.1 Red Hat Enterprise Linux 9.6 Extended Update Support 2026-08-06T00:00:00Z RHSA-2026:51059 libXfont2-0:2.0.3-12.el9_6.1 https://www.cve.org/CVERecord?id=CVE-2026-56002 https://nvd.nist.gov/vuln/detail/CVE-2026-56002