CVE-2026-41650

fast-xml-parser XMLBuilder: XML Comment and CDATA Injection via Unescaped Delimiters

fast-xml-parser allows users to process XML from JS object without C/C++ based libraries or callbacks. Prior to version 5.7.0, XMLBuilder does not escape the "-->" sequence in comment content or the "]]>" sequence in CDATA sections when building XML from JavaScript objects. This allows XML injection when user-controlled data flows into comments or CDATA elements, leading to XSS, SOAP injection, or data manipulation. This issue has been patched in version 5.7.0.

Affected

NaturalIntelligence · fast-xml-parser

CVSS v3.1 GITHUB

6.1 MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

EPSS

0.27% chance of exploitation in the next 30 days, 18th percentile

Published

2026-05-07

Proof-of-concept exploits (1)

• advisories/GHSA-gh4j-gqv2-49f6

Security advisories

• NaturalIntelligence/fast-xml-parser/security/advisories/GHSA-gh4j-gqv2-49f6
• NaturalIntelligence/fast-xml-parser/releases/tag/v5.6.0

References

• CVE Record
• NVD entry