Protection mechanism failure in expat - CVE-2026-50219

Vulnerability identifier: #VU144338

CSH Severity: Medium

CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-50219

CWE-ID: CWE-693

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to cause memory corruption.

The vulnerability exists due to missing control flow integrity checks in XML_GetBuffer, XML_Parse, XML_ParseBuffer, XML_ParserFree, and XML_ParserReset when these functions are called reentrantly from bindings or callbacks. A remote attacker can trigger unsafe parser API calls to cause memory corruption.

The issue is described as relevant to language bindings.

expat
LANTIME Operating System Firmware (LTOS)
openEuler
Anolis OS
Fedora
expat
expat-debuginfo
expat-debugsource
expat-devel
expat-help
expat-static
expat-doc
mingw-expat

Install security update from vendor's website.

expat - update to 2.8.2
LANTIME Operating System Firmware (LTOS) - update to 7.10.013
expat - addressed in versions 2.2.9-26, 2.2.9-27, 2.2.9-28, 2.4.1-26, 2.4.1-27, 2.5.0-21, 2.5.0-22, 2.5.0-23
expat-debuginfo - addressed in versions 2.2.9-26, 2.2.9-27, 2.2.9-28, 2.4.1-26, 2.4.1-27, 2.5.0-21, 2.5.0-22, 2.5.0-23
expat-debugsource - addressed in versions 2.2.9-26, 2.2.9-27, 2.2.9-28, 2.4.1-26, 2.4.1-27, 2.5.0-21, 2.5.0-22, 2.5.0-23
expat-devel - addressed in versions 2.2.9-26, 2.2.9-27, 2.2.9-28, 2.4.1-26, 2.4.1-27, 2.5.0-21, 2.5.0-22, 2.5.0-23
expat-help - addressed in versions 2.2.9-26, 2.2.9-27, 2.2.9-28, 2.4.1-26, 2.4.1-27, 2.5.0-21, 2.5.0-22, 2.5.0-23
expat - addressed in versions 2.5.0-14, 2.5.0-16
expat-devel - addressed in versions 2.5.0-14, 2.5.0-16
expat-static - addressed in versions 2.5.0-14, 2.5.0-16
expat-doc - addressed in versions 2.5.0-14, 2.5.0-16
mingw-expat - addressed in versions 2.8.2-1.fc43, 2.8.2-1.fc44

• https://seclists.org/oss-sec/2026/q2/1030
• https://github.com/python/cpython/issues/146169

• Multiple vulnerabilities in libexpat
• Multiple vulnerabilities in Meinberg LANTIME firmware
• Fedora 44 update for mingw-expat
• Fedora 43 update for mingw-expat
• openEuler update for expat
• openEuler 24.03 LTS SP3 update for expat
• openEuler 24.03 LTS SP1 update for expat
• openEuler 22.03 LTS SP4 update for expat
• openEuler 20.03 LTS SP4 update for expat
• openEuler 24.03 LTS SP3 update for expat
• openEuler 24.03 LTS SP1 update for expat
• openEuler 22.03 LTS SP4 update for expat
• openEuler 20.03 LTS SP4 update for expat
• Anolis OS update for expat
• Anolis OS update for expat