CVE-2026-25896 — fast-xml-parser has an entity encoding bypass via regex injection in DOCTYPE entity names
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…
Published: 2026-02-20 · CVSS: 9.3 · CVSS 3.1
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 built-in XML entities (<, >, &, ", ') with arbitrary values. This bypasses entity encoding and leads to XSS when parsed output is rendered. This vulnerability is fixed in 5.3.5.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7