CVE-2026-44664: fast-xml-builder Comment Value regex can be bypassed

May 8, 2026 (updated May 14, 2026)

The fix for https://github.com/advisories/GHSA-gh4j-gqv2-49f6 in fast-xml-parser sanitizes -- sequences in XML comment content using .replace(/–/g, ‘- -’). This skip the values containing three consecutive dashes (e.g., —>…), allowing an attacker to break out of an XML comment and inject arbitrary XML/HTML content.

References

github.com/NaturalIntelligence/fast-xml-builder/security/advisories/GHSA-45c6-75p6-83cc
github.com/NaturalIntelligence/fast-xml-parser/security/advisories/GHSA-gh4j-gqv2-49f6
github.com/advisories/GHSA-45c6-75p6-83cc
nvd.nist.gov/vuln/detail/CVE-2026-44664

Code Behaviors & Features

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