Nokogiri before 1.18.4 bundles a vulnerable version of libxslt (prior to 1.1.43) that contains two use-after-free vulnerabilities: CVE-2025-24855 (use-after-free of the XPath context node due to xsltEvalXPathStringNs leaking xpathCtxt->node) and CVE-2024-55549 (use-after-free related to excluded result prefixes/namespaces). Processing crafted XSLT can trigger memory corruption. Nokogiri 1.18.4 upgrades the bundled libxslt to 1.1.43 to resolve these issues.

Nokogiri versions prior to 1.18.4 bundle a vulnerable version of libxslt (prior to 1.1.43) that contains two use-after-free vulnerabilities. CVE-2025-24855 involves a use-after-free of the XPath context node due to xsltEvalXPathStringNs leaking xpathCtxt->node. CVE-2024-55549 involves a use-after-free related to excluded result prefixes and namespaces. Processing specially crafted XSLT input can trigger memory corruption exploiting these flaws. The vulnerabilities are inherited through Nokogiri's bundled dependency on libxslt, representing a supply chain risk. Nokogiri 1.18.4 resolves both issues by upgrading the bundled libxslt to version 1.1.43. Users of Nokogiri are advised to upgrade to version 1.18.4 or later immediately.