XML External Entity (XXE)

fast-xml-parser is vulnerable to XML External Entity XXE. The vulnerability is due to improper handling of a dot . in DOCTYPE entity names, which is treated as a regex wildcard during entity replacement, allowing an attacker to shadow built-in XML entities and bypass entity encoding, thereby...

CVE-2026-25896

fast-xml-parser allows users to validate XML, parse XML to JS object, or build XML from JS object without C/C++ based libraries and no callback. From 4.1.3to before 5.3.5, a dot . in a DOCTYPE entity name is treated as a regex wildcard during entity replacement, allowing an attacker to shadow...

CVE-2026-25896

fast-xml-parser allows users to validate XML, parse XML to JS object, or build XML from JS object without C/C++ based libraries and no callback. From 4.1.3to before 5.3.5, a dot . in a DOCTYPE entity name is treated as a regex wildcard during entity replacement, allowing an attacker to shadow...

PT-2026-21298

Name of the Vulnerable Software and Affected Versions fast-xml-parser versions 4.1.3 through 5.3.5 Description fast-xml-parser has a flaw in how it handles DOCTYPE entity names during XML parsing. Specifically, a dot . within an entity name is treated as a regex wildcard during entity replacement...