Vulnerability · Published May 13, 2026 · Assigned by GitHub_M
CVE-2026-44665fast-xml-builder: Attribute values with unwanted quotes can bypass malicious or unwanted attributes
Medium 6.1
In plain English
A medium-severity security flaw in fast-xml-builder 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-builder builds XML from JSON. Prior to 1.1.7, when an input data has quotes in attribute values but process entities is not enabled, it breaks the attribute value into multiple attributes. This gives the room for an attacker to insert unwanted attributes to the XML/HTML. This vulnerability is fixed in 1.1.7.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| npm | fast-xml-builder | 1.1.7 | GHSA-5wm8-gmm8-39j9 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| NaturalIntelligence | fast-xml-builder | < 1.1.7 |
Weakness: CWE-91 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N