Ubuntu: USN-7974-1 (CVE-2026-0992): libxml2 vulnerabilities

It was discovered that libxml2 incorrectly handled maliciously crafted SGML
catalog files. An attacker could possibly use this issue to cause libxml2
to consume excessive resources, leading to a denial of service.
(CVE-2025-8732)

It was discovered that libxml2 incorrectly handled recursive include
directories with the RelaxNG parser. An attacker could possibly use this
issue to cause libxml2 to consume excessive resources, leading to a denial
of service. (CVE-2026-0989)

Nick Wellnhofer discovered that libxml2 incorrectly parsed catalogs with
self-referencing URI delegates. An attacker could possibly use this issue
to cause libxml2 to consume excessive resources, leading to a denial of
service. (CVE-2026-0990)

Nick Wellnhofer discovered that libxml2 inefficiently parsed catalogs
linked with repeating nextCatalog elements. An attacker could possibly use
this issue to cause libxml2 to use excessive resources, leading to a denial
of service. (CVE-2026-0992)