Description

Summary

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.

Impact

Any application with comment property enabled allow attacker to inject malicious or unwanted code like JS script tag in the XML/HTML output.

Workarounds

Check for the presence of 3 consecutive dashes externally in the property value used for comment tag.

Basic information

Type: reviewed
Severity: medium
Advisory on GitHub: Open advisory ↗
Repository advisory: Open repository advisory ↗
Source code: Browse source ↗
Published (advisory): 2026-05-08 16:27:28 UTC
Updated: 2026-05-14 20:37:34 UTC
GitHub reviewed: 2026-05-08 16:27:28 UTC
NVD published: 2026-05-13

Score	Percentile
0.03%	8.44%

CVSS Scores

Base score	Version	Severity	Vector
6.1	3.1	—	`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N` Click to expand Attack vector (AV:N) Could be attacked over the internet or any normal routed network—not just someone sitting at the machine. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:N) No account or special rights needed—anonymous or random user is enough. User interaction (UI:R) A real person has to do something—click, install, enable—otherwise it doesn’t land. Scope (S:C) Breaking this can reach past the original component and bite other resources—bigger blast radius. Confidentiality (C:L) Some sensitive info could get out, but not a total data dump. Integrity (I:L) Attackers could change some data, but it’s limited—not everything goes. Availability (A:N) Service keeps running; no real outage angle.

Identifiers

Type	Value
GHSA	GHSA-45c6-75p6-83cc ↗
CVE	CVE-2026-44664 ↗

CWEs

CWE id	Name
CWE-91	XML Injection (aka Blind XPath Injection)

Credits

amitguptagwl (other)

Affected packages (1)

Vulnerable version ranges and first patched releases as published by GitHub.

Ecosystem	Package	Vulnerable range	First patched	Vulnerable functions
npm	fast-xml-builder	= 1.1.5	1.1.6	—

fast-xml-builder Comment Value regex can be bypassed