CVE-2026-25896CRITICAL 9.3EPSS p35.6%
CVE-2026-25896CVE-2026-25896
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.
Scoring
| CVSS 3.1 | 9.3 (CRITICAL) |
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:N |
| EPSS | 0.45% probability of exploitation · percentile 35.6% · 2026-06-19T12:03:05Z |
| Published | 2026-02-20 |
| Last modified | 2026-03-02 |
Underlying weaknesses· 1
References
- 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://github.com/NaturalIntelligence/fast-xml-parser/security/advisories/GHSA-m7jm-9gc2-mpf2
1
| Type | Target | Confidence | Tier |
|---|---|---|---|
| Weakness | Incorrect Regular Expressioncwe-185 | 0% | live |
Related by meaning· 6
Nearest entities by semantic similarity across the cs-graph corpus.