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

Install security update from vendor's website.

expat - update to 2.8.2
LANTIME Operating System Firmware (LTOS) - update to 7.10.013
expat (Ubuntu package) - addressed in versions 2.1.0-4ubuntu1.4+esm12, 2.1.0-7ubuntu0.16.04.5+esm13, 2.2.5-3ubuntu0.9+esm4, 2.2.9-1ubuntu0.8+esm2, 2.4.7-1ubuntu0.8, 2.6.1-2ubuntu0.5, 2.7.4-1ubuntu0.1
expat-debuginfo - addressed in versions 2.2.9-26, 2.2.9-27, 2.2.9-28, 2.2.9-33, 2.4.1-26, 2.4.1-27, 2.4.1-31, 2.5.0-21, 2.5.0-22, 2.5.0-23, 2.5.0-27, 2.8.1-8
expat-debugsource - addressed in versions 2.2.9-26, 2.2.9-27, 2.2.9-28, 2.2.9-33, 2.4.1-26, 2.4.1-27, 2.4.1-31, 2.5.0-21, 2.5.0-22, 2.5.0-23, 2.5.0-27, 2.8.1-8
expat-devel - addressed in versions 2.2.9-26, 2.2.9-27, 2.2.9-28, 2.2.9-33, 2.4.1-26, 2.4.1-27, 2.4.1-31, 2.5.0-21, 2.5.0-22, 2.5.0-23, 2.5.0-27, 2.8.1-8
expat-help - addressed in versions 2.2.9-26, 2.2.9-27, 2.2.9-28, 2.2.9-33, 2.4.1-26, 2.4.1-27, 2.4.1-31, 2.5.0-21, 2.5.0-22, 2.5.0-23, 2.5.0-27, 2.8.1-8
expat - addressed in versions 2.2.9-26, 2.2.9-27, 2.2.9-28, 2.2.9-33, 2.4.1-26, 2.4.1-27, 2.4.1-31, 2.5.0-21, 2.5.0-22, 2.5.0-23, 2.5.0-27, 2.8.1-8
expat - addressed in versions 2.5.0-2, 2.5.0-14, 2.5.0-16
expat-devel - addressed in versions 2.5.0-2, 2.5.0-14, 2.5.0-16
expat-doc - addressed in versions 2.5.0-14, 2.5.0-16
expat-static - 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
expat (Debian package) - update to 2.8.2-1~deb13u1

• 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
• Debian 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 SP4 update for expat
• Anolis OS update for expat
• Ubuntu update for expat