Description
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.
Affected products
Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.
NaturalIntelligence fast-xml-parser
>= 5.0.0, < 5.3.5affected>= 4.1.3, < 4.5.4affected
References
- https://github.com/NaturalIntelligence/fast-xml-parser/security/advisories/GHSA-m7jm-9gc2-mpf2 ↗
- https://github.com/NaturalIntelligence/fast-xml-parser/commit/943ef0eb1b2d3284e72dd74f44a042ee9f07026e ↗
- https://github.com/NaturalIntelligence/fast-xml-parser/commit/ddcd0acf26ddd682cb0dc15a2bd6aa3b96bb1e69 ↗
- https://github.com/NaturalIntelligence/fast-xml-parser/releases/tag/v5.3.5 ↗
- https://access.redhat.com/security/cve/CVE-2026-25896 ↗
- https://bugzilla.redhat.com/show_bug.cgi?id=2441501 ↗
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-25896.json ↗
- https://access.redhat.com/errata/RHSA-2026:7110 ↗
- https://access.redhat.com/errata/RHSA-2026:7128 ↗
- https://access.redhat.com/errata/RHSA-2026:6174 ↗
- https://access.redhat.com/errata/RHSA-2026:6802 ↗
- https://access.redhat.com/errata/RHSA-2026:41941 ↗
- https://access.redhat.com/errata/RHSA-2026:41944 ↗
- https://access.redhat.com/errata/RHSA-2026:40984 ↗
- https://access.redhat.com/errata/RHSA-2026:51349 ↗