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

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

4.4 · CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:N

EPSS

• CVE-2026-42140: 0.18% estimated exploitation activity in the next 30 days; percentile 7.51 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Impact 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 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. 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 by the commit c8b19bda93058794e04c8862fc7ca85c59b5fe5c. For more information If there are any questions or comments about this advisory: Open an issue in JIRA XWiki.org Send an email to…

Published by the source

5 May 2026, 19:32 UTC

Last modified by the source

5 May 2026, 19:32 UTC

Source last checked

26 Oct 2026, 16:45 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-42fc-7w97-8vrc

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# Patch Next advisory brief: CVE-2026-42140

Advisory: XWiki PlantUML Macro Vulnerable to Server-Side Request Forgery (SSRF) via 'server' parameter
IDs: CVE-2026-42140, GHSA-42fc-7w97-8vrc
Record: https://patchnext.com/advisories/cve-2026-42140 (revision 1, source checked 26 Oct 2026, 16:45 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 4.4)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: org.xwiki.contrib.plantuml:macro-plantuml-macro 2.4.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- Maven org.xwiki.contrib.plantuml:macro-plantuml-macro: affected < 2.4.1; fixed in 2.4.1

## Suggested inspection (read-only)
- Maven org.xwiki.contrib.plantuml:macro-plantuml-macro: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on org.xwiki.contrib.plantuml:macro-plantuml-macro.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-42fc-7w97-8vrc (GitHub-reviewed advisory GHSA-42fc-7w97-8vrc lists affected ranges: Maven org.xwiki.contrib.plantuml:macro-plantuml-macro >=0 <2.4.1)

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