Vulnerability · Published May 7, 2026 · Assigned by GitHub_M
CVE-2026-41650fast-xml-parser XMLBuilder: XML Comment and CDATA Injection via Unescaped Delimiters
Medium 6.1
In plain English
A medium-severity security flaw in fast-xml-parser from NaturalIntelligence. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 15% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
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 packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | node-webfont | no fix listed | DEBIAN-CVE-2026-41650 |
| Debian:13 | node-webfont | no fix listed | DEBIAN-CVE-2026-41650 |
| Debian:14 | node-webfont | no fix listed | DEBIAN-CVE-2026-41650 |
| Ubuntu:24.04:LTS | node-webfont | no fix listed | UBUNTU-CVE-2026-41650 |
| Ubuntu:25.10 | node-webfont | no fix listed | UBUNTU-CVE-2026-41650 |
| Ubuntu:26.04:LTS | node-webfont | no fix listed | UBUNTU-CVE-2026-41650 |
| Ubuntu:26.10 | node-webfont | no fix listed | UBUNTU-CVE-2026-41650 |
| npm | fast-xml-parser | 5.7.0 | GHSA-gh4j-gqv2-49f6 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| NaturalIntelligence | fast-xml-parser | < 5.7.0 |
Weakness: CWE-91 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N