CVE-2026-42140
Server-Side Request Forgery (SSRF) in PlantUML Macro via 'server' parameter
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- Low
- User interaction
- Required
What an attacker can affect
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
Server-Side Request Forgery (SSRF) in PlantUML Macro via 'server' parameter
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.
- Record
CVE-2026-42140- CVSS 3.1
- 4.4 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:N - Weakness
- CWE-918
- Updated
- 2026-11-02
EUVDEUVD-2026-27073
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.
- Record
EUVD-2026-27073- CVSS 3.1
- 4.4 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-42fc-7w97-8vrc
XWiki PlantUML Macro Vulnerable to Server-Side Request Forgery (SSRF) via 'server' parameter
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 Security Mailing List
Attribution
The issue was reported by Łukasz Rybak.
- Record
GHSA-42fc-7w97-8vrc- CVSS 3.1
- 4.4 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:N - Weakness
- CWE-918
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2026-42140- CVSS 3.1
- 4.4 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:N - Weakness
- CWE-918
- Updated
- 2026-11-02
OSV
Server-Side Request Forgery (SSRF) in PlantUML Macro via 'server' parameter
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.
- Record
CVE-2026-42140- CVSS 3.1
- 4.4 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:N - Weakness
- CWE-918
- Updated
- 2026-11-02
OSVGHSA-42fc-7w97-8vrc
XWiki PlantUML Macro Vulnerable to Server-Side Request Forgery (SSRF) via 'server' parameter
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 Security Mailing List
Attribution
The issue was reported by Łukasz Rybak.
- Record
GHSA-42fc-7w97-8vrc- CVSS 3.1
- 4.4 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:N - Weakness
- CWE-918
- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
org.xwiki.contrib.plantuml:macro-plantuml-macroMaven |
before 2.4.1 | 2.4.1 |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-42140 is a medium vulnerability (CVSS 4.4) in Xwiki-contrib Macro-plantuml, published May 4, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.18%, the 7th percentile. Fixed in org.xwiki.contrib.plantuml:macro-plantuml-macro 2.4.1.
References
github.com/xwiki-contrib/macro-plantuml/security/advisories/GHSA-42fc-7w97-8vrc
jira.xwiki.org/browse/PLANTUML-25
nvd.nist.gov/vuln/detail/CVE-2026-42140