fast-xml-parser has RangeError DoS Numeric Entities Bug

Description

A RangeError vulnerability exists in the numeric entity processing of fast-xml-parser when parsing XML with out-of-range entity code points (e.g., � or �). This causes the parser to throw an uncaught exception, crashing any application that processes untrusted XML input.

Recommendation

Update the fast-xml-parser package to the latest compatible version. Followings are version details:

• Affected version(s): >= 5.0.9, <= 5.3.3
• Patched version(s): 5.3.4

References

• GHSA-37qj-frw5-hhjh
• CVE-2026-25128
• CWE-20
• CWE-248
• CAPEC-310
• OWASP 2021-A3
• OWASP 2021-A6

Related Issues

• fast-xml-parser affected by DoS through entity expansion in DOCTYPE (no expansion limit) - CVE-2026-26278
• fast-xml-parser has an entity encoding bypass via regex injection in DOCTYPE entity names - CVE-2026-25896
• fast-xml-parser has stack overflow in XMLBuilder with preserveOrder - CVE-2026-27942
• fast-xml-parser affected by numeric entity expansion bypassing all entity expansion limits (incomplete fix for CVE-2026- - CVE-2026-33036

Tags:

npm

fast-xml-parser