Affected: libexpat project libexpat, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat JBoss Core Services 2.4.62.SP4, Red Hat Discovery 2, Red Hat Update Infrastructure 5, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP and 2 more

In libexpat before 2.8.1, the computational complexity of attribute name collision checks allows a denial of service via moderately sized crafted XML input.

Affected: Ubuntu:Pro:14.04:LTS: expat, Ubuntu:Pro:16.04:LTS: expat, Ubuntu:Pro:18.04:LTS: expat, Ubuntu:Pro:20.04:LTS: expat, Ubuntu:22.04:LTS: expat, Ubuntu:24.04:LTS: expat, Ubuntu:26.04:LTS: expat

It was discovered that Expat could be made to allocate large amounts of memory when parsing a small crafted document. An attacker could possibly use this issue to cause Expat to consume resources, leading to a denial of service. This issue was only addressed in Ubuntu 24.04 LTS. (CVE-2025-59375)

It was discovered that Expat incorrectly handled empty external parameter entity content. An attacker could possibly use this issue to cause Expat to crash, resulting in a denial of service. (CVE-2026-32776)

It was discovered that Expat incorrectly handled certain DTD content. An attacker could possibly use this issue to cause Expat to enter an infinite loop, resulting in a denial of service. (CVE-2026-32777)

It was discovered that Expat incorrectly handled memory when retrying after an earlier out-of-memory condition. An attacker could possibly use this issue to cause Expat to crash, resulting in a denial of service. (CVE-2026-32778)

It was discovered that Expat performed attribute name collision checks inefficiently. An attacker could possibly use this issue to cause Expat to consume resources when processing a moderately sized crafted XML document, resulting in a denial of service. This issue was only addressed in Ubuntu 24.04 LTS and Ubuntu 26.04 LTS. (CVE-2026-45186)

It was discovered that Expat used insufficient entropy, allowing hash flooding through a crafted XML document. An attacker could possibly use this issue to cause Expat to consume resources, leading to a denial…