CVE-2026-44665: fast-xml-builder allows attribute values with unwanted quotes to bypass malicious or unwanted attributes

May 8, 2026

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.

References

github.com/NaturalIntelligence/fast-xml-builder
github.com/NaturalIntelligence/fast-xml-builder/security/advisories/GHSA-5wm8-gmm8-39j9
github.com/advisories/GHSA-5wm8-gmm8-39j9
nvd.nist.gov/vuln/detail/CVE-2026-44665

Code Behaviors & Features

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