CVE-2026-33036
CVE-2026-33036 · fast-xml-parser affected by numeric entity expansion bypassing all entity expansion limits (incomplete fix for CVE-2026-26278)
This page contains facts from public vulnerability sources. Check the original advisory before updating.
fast-xml-parser allows users to process XML from JS object without C/C++ based libraries or callbacks. Versions 4.0.0-beta.3 through 5.5.5 contain a bypass vulnerability where numeric character references (&#NNN;, &#xHH;) and standard XML entities completely evade the entity expansion limits (e.g., maxTotalExpansions, maxExpandedLength) added to fix CVE-2026-26278, enabling XML entity expansion Denial of Service. The root cause is that replaceEntitiesValue() in OrderedObjParser.js only enforces expansion counting on DOCTYPE-defined entities while the lastEntities loop handling numeric/standard entities performs no counting at all. An attacker supplying 1M numeric entity references like A can force ~147MB of memory allocation and heavy CPU usage, potentially crashing the process—even when developers have configured strict limits. This issue has been fixed in version 5.5.6.
CVSS 7.5 · High · EPSS 0.6% · Fix available
- Published
- Updated
Affected products and versions
fast-xml-parser
- Versions
- >= 4.0.0-beta.3, < 5.5.6: Affected
No fix published
node-webfont Debian:12
- Versions
- 11.4.0+dfsg2+~cs35.7.26-10
- 11.4.0+dfsg2+~cs35.7.26-11
- 11.4.0+dfsg2+~cs35.7.26-12
- 11.4.0+dfsg2+~cs35.7.26-13
- 11.4.0+dfsg2+~cs35.7.26-14
- 11.4.0+dfsg2+~cs35.7.26-15
- 11.4.0+dfsg2+~cs35.7.26-16
- 11.4.0+dfsg2+~cs35.7.26-18
- 11.4.0+dfsg2+~cs35.7.26-19
- 11.4.0+dfsg2+~cs35.7.26-20
- 11.4.0+dfsg2+~cs35.7.26-21
- 11.4.0+dfsg2+~cs35.7.26-7
- 11.4.0+dfsg2+~cs35.7.26-8
- 11.4.0+dfsg2+~cs35.7.26-9
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
node-webfont Debian:13
- Versions
- 11.4.0+dfsg2+~cs35.7.26-13
- 11.4.0+dfsg2+~cs35.7.26-14
- 11.4.0+dfsg2+~cs35.7.26-15
- 11.4.0+dfsg2+~cs35.7.26-16
- 11.4.0+dfsg2+~cs35.7.26-18
- 11.4.0+dfsg2+~cs35.7.26-19
- 11.4.0+dfsg2+~cs35.7.26-20
- 11.4.0+dfsg2+~cs35.7.26-21
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
node-webfont Debian:14
- Versions
- 11.4.0+dfsg2+~cs35.7.26-13
- 11.4.0+dfsg2+~cs35.7.26-14
- 11.4.0+dfsg2+~cs35.7.26-15
- 11.4.0+dfsg2+~cs35.7.26-16
- 11.4.0+dfsg2+~cs35.7.26-18
- 11.4.0+dfsg2+~cs35.7.26-19
- 11.4.0+dfsg2+~cs35.7.26-20
- 11.4.0+dfsg2+~cs35.7.26-21
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
fast-xml-parser npm
- Affected ranges
- SEMVER: ≥ 5.0.0, < 5.5.6
Update to 5.5.6
fast-xml-parser npm
- Affected ranges
- SEMVER: ≥ 4.0.0-beta.3, < 4.5.5
Update to 4.5.5
node-webfont Ubuntu:24.04:LTS
- Versions
- 11.4.0+dfsg2+~cs35.7.26-7ubuntu1
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
node-webfont Ubuntu:25.10
- Versions
- 11.4.0+dfsg2+~cs35.7.26-10
- 11.4.0+dfsg2+~cs35.7.26-13ubuntu2
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
node-webfont Ubuntu:26.10
- Versions
- 11.4.0+dfsg2+~cs35.7.26-18
- 11.4.0+dfsg2+~cs35.7.26-19
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
node-webfont Ubuntu:26.04:LTS
- Versions
- 11.4.0+dfsg2+~cs35.7.26-13ubuntu2
- 11.4.0+dfsg2+~cs35.7.26-14
- 11.4.0+dfsg2+~cs35.7.26-15
- 11.4.0+dfsg2+~cs35.7.26-16build1
- 11.4.0+dfsg2+~cs35.7.26-18
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
Original sources
- https://github.com/NaturalIntelligence/fast-xml-parser/security/advisories/GHSA-8gc5-j5rx-235r
- https://github.com/NaturalIntelligence/fast-xml-parser/commit/bd26122c838e6a55e7d7ac49b4ccc01a49999a01
- https://github.com/NaturalIntelligence/fast-xml-parser/releases/tag/v5.5.6
- https://nvd.nist.gov/vuln/detail/CVE-2026-33036