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
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| NaturalIntelligence | fast-xml-parser | >= 5.0.0, < 5.3.5, >= 4.1.3, < 4.5.4 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | node-webfont | No fix yet | — |
| Debian 13 | node-webfont | No fix yet | — |
| Debian 12 | node-webfont | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | node-webfont | No fix yet | — |
| Ubuntu 26.04 LTS | node-webfont | No fix yet | — |
| Ubuntu 25.10 | node-webfont | No fix yet | — |
| Ubuntu 24.04 LTS | node-webfont | No fix yet | — |
Wolfi
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Wolfi rolling | prism | 5.14.3-r7 | — |
| Wolfi rolling | renovate | 43.48.3-r0 | — |
| Wolfi rolling | saf | 1.6.0-r0 | — |
| Wolfi rolling | tileserver-gl | 5.5.0-r5 | — |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| npm | fast-xml-parser | >= 5.0.0, < 5.3.5 | 5.3.5 | GHSA-m7jm-9gc2-mpf2 |
| npm | fast-xml-parser | >= 4.1.3, < 4.5.4 | 4.5.4 | GHSA-m7jm-9gc2-mpf2 |
Advisories 2
- SCA-2026-0014 Fast-xml-parser vulnerabilities affect Sentio Creator Extension 'Device Manager' SICK PSIRT · Oct 14, 2026
- WID-SEC-2026-0772 IBM App Connect Enterprise (fast-xml-parser): Mehrere Schwachstellen BSI CERT-Bund (WID) · May 21, 2026
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