NaturalIntelligence fast-xml-parser up to 5.6.x CDATA Section xml injection

Summaryinfo

A vulnerability was found in NaturalIntelligence fast-xml-parser up to 5.6.x. It has been rated as critical. Affected by this issue is some unknown functionality of the component CDATA Section. This manipulation causes xml injection. The identification of this vulnerability is CVE-2026-41650. It is possible to initiate the attack remotely. There is no exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in NaturalIntelligence fast-xml-parser up to 5.6.x. It has been declared as critical. Affected by this vulnerability is an unknown function of the component CDATA Section. The manipulation with an unknown input leads to a xml injection vulnerability. The CWE definition for the vulnerability is CWE-91. The product does not properly neutralize special elements that are used in XML, allowing attackers to modify the syntax, content, or commands of the XML before it is processed by an end system. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

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.

It is possible to read the advisory at github.com. This vulnerability is known as CVE-2026-41650 since 04/22/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. The technical details are unknown and an exploit is not publicly available. The attack technique deployed by this issue is T1505 according to MITRE ATT&CK.

Upgrading to version 5.7.0 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at CERT Bund (WID-SEC-2026-1654). Be aware that VulDB is the high quality source for vulnerability data.

Affected

• IBM App Connect Enterprise

Productinfo

Vendor

• NaturalIntelligence

Name

• fast-xml-parser

Version

• 5.0
• 5.1
• 5.2
• 5.3
• 5.4
• 5.5
• 5.6

Website

• Product: https://github.com/NaturalIntelligence/fast-xml-parser/

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Be aware that VulDB is the high quality source for vulnerability data.

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