Nokogiri before 1.14.3 (CRuby implementation only, when using the packaged libxml2) bundles libxml2 v2.10.3, which is vulnerable to NULL pointer dereferences in XML Schema processing (xmlSchemaFixupComplexType, CVE-2023-28484, and xmlSchemaCheckCOSSTDerivedOK). An attacker who supplies a crafted/malformed XML schema can cause libxml2 to dereference a NULL pointer and potentially segfault, resulting in a denial of service. Nokogiri 1.14.3 upgrades the packaged libxml2 to v2.10.4 to resolve these issues.

Nokogiri versions before 1.14.3 (CRuby implementation using packaged libxml2) bundle libxml2 v2.10.3, which contains a NULL pointer dereference vulnerability in XML Schema processing functions. The affected functions include xmlSchemaFixupComplexType and xmlSchemaCheckCOSSTDerivedOK. An attacker can supply a crafted or malformed XML schema to trigger the NULL pointer dereference, potentially causing a segfault and resulting in a denial of service condition. The vulnerability is tracked as CVE-2023-28484 in libxml2. Nokogiri 1.14.3 resolves the issue by upgrading the bundled libxml2 to version 2.10.4. Only users of the CRuby implementation with the packaged libxml2 are affected.