CVE-2026-42140
Deferred Deferred - Pending Action
Server-Side Request Forgery in PlantUML Macro for XWiki

Publication date: 2026-05-04

Last updated on: 2026-05-07

Assigner: GitHub, Inc.

Description
PlantUML Macro is a macro for rendering UML diagrams from simple textual schemes. Prior to version 2.4.1, the PlantUML Macro is vulnerable to Server-Side Request Forgery (SSRF). The macro allows users to specify an alternative PlantUML server via the server parameter. However, the application does not validate the supplied URL. An attacker can supply an internal IP address or a malicious external URL. The XWiki server will attempt to connect to this URL to "render" the diagram. This issue has been patched in version 2.4.1.
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Meta Information
Published
2026-05-04
Last Modified
2026-05-07
Generated
2026-06-16
AI Q&A
2026-05-05
EPSS Evaluated
2026-06-15
NVD
CVE-2026-42140
EUVD
EUVD-2026-27073
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
plantuml macro to 2.4.1 (exc)
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-918 The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.
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Executive Summary

The vulnerability exists in the PlantUML Macro, which is used to render UML diagrams from simple text. Before version 2.4.1, the macro allowed users to specify an alternative PlantUML server via a server parameter without validating the supplied URL. This lack of validation enables an attacker to provide an internal IP address or a malicious external URL. As a result, the XWiki server attempts to connect to this attacker-controlled URL to render the diagram, leading to a Server-Side Request Forgery (SSRF) vulnerability.

Impact Analysis

This SSRF vulnerability can allow an attacker to make the XWiki server send requests to internal or external systems that the attacker normally cannot access. This could lead to unauthorized access to internal network resources, information disclosure, or interaction with internal services. The attacker might exploit this to gather sensitive information or perform further attacks within the internal network.

Mitigation Strategies

To mitigate this vulnerability, you should upgrade the PlantUML Macro to version 2.4.1 or later, where the issue has been patched.

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