🛡️ CVE-2026-42140 — macro-plantuml-macro

🟡 CVSS 4.4 — Medium ✅ No Known Exploit CWE-918 NVD
4.4
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

XWiki PlantUML Macro Vulnerable to Server-Side Request Forgery (SSRF) via 'server' parameter

Impact

The [PlantUML Macro](https://extensions.xwiki.org/xwiki/bin/view/Extension/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 affects all versions of the Plant UML Macro extension till version 2.4 included.

Patches

Version 2.4.1 of the Plant UML Macro extension fixes the issue by verifying if the supplied server domain matches one of the [trusted domain configured inside of XWiki](https://www.xwiki.org/xwiki/bin/view/Documentation/AdminGuide/Configuration/#HTrusteddomains).

Workarounds

Protect the XWiki server by placing it in a DMZ so that it cannot access any other internal servers.

Resources

The issue was fixed in [PLANTUML-25](https://jira.xwiki.org/browse/PLANTUML-25) by the commit [c8b19bda93058794e04c8862fc7ca85c59b5fe5c](https://github.com/xwiki-contrib/macro-plantuml/commit/c8b19bda93058794e04c8862fc7ca85c59b5fe5c).

For more information

If there are any questions or comments about this advisory:

Attribution

The issue was reported by Łukasz Rybak.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is high, an attacker needs low-level privileges on the target. A user must be tricked into taking some action. The scope is changed, meaning a successful attack can affect components beyond the vulnerable one. Rated impact: confidentiality low, integrity low, availability none.

Weakness class

CVE-2026-42140 is classified as CWE-918: Server-Side Request Forgery (SSRF). The server fetches a URL supplied by the caller, which can be pointed at internal systems it alone can reach.

Affected software

CVE-2026-42140 is recorded against 2 packages.

  • org.xwiki.contrib.plantuml:macro-plantuml-macro (fixed in 2.4.1)
  • unknown

Timeline and source

Published on 5 May 2026. No public exploit is currently recorded for this entry. Record sourced from NVD.

References

github.com (Web)
nvd.nist.gov (Advisory)
github.com (Web)
github.com (Package)
jira.xwiki.org (Web)

Details

Severity Medium
CVSS Score 4.4
CVSS Vector CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:N
CWE CWE-918
Public Exploit ✅ No
Source NVD
Published 2026-05-05
Updated 2026-08-12
Modified 2026-05-05
Fix URL N/A

Affected Packages

Software From version Fixed in
org.xwiki.contrib.plantuml:macro-plantuml-macro 2.4.1
unknown

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