Vulnerability · Published May 13, 2026 · Assigned by GitHub_M

CVE-2026-44664fast-xml-builder: Comment Value bypass regex

Medium 6.1

In plain English

A medium-severity security flaw in fast-xml-builder from NaturalIntelligence. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 9% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)6.1Medium

Exploit odds (30 days)0.2%top 90.9% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

fast-xml-builder builds XML from JSON. In 1.1.5, the fix for CVE-2026-41650 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. This vulnerability is fixed in 1.1.6.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
npm	fast-xml-builder	1.1.6	GHSA-45c6-75p6-83cc

Affected products (as reported)

Vendor	Product	Versions
NaturalIntelligence	fast-xml-builder	1.1.5

Weakness: CWE-91 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

References

https://github.com/NaturalIntelligence/fast-xml-builder/security/advisories/GHSA-45c6-75p6-83cc x_refsource_CONFIRM