CVE-2026-25896
9.3
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:N
Summary
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 Software
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| NaturalIntelligence | fast-xml-parser | >= 5.0.0, < 5.3.5 | affected |
| NaturalIntelligence | fast-xml-parser | >= 4.1.3, < 4.5.4 | affected |
Weaknesses
- CWE-185: CWE-185: Incorrect Regular Expression
ADP Enrichment
CISA ADP Vulnrichment
- SSVC:
- Exploitation: poc
- Automatable: yes
- Technical Impact: partial
fast-xml-parser: fast-xml-parser: Cross-Site Scripting (XSS) due to improper DOCTYPE entity handling
Additional References
- 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
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
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