CVE-2026-42140: 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-S...

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.

Metrics

CVSS 3.1

4.4/10

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

EPSS Probability

0.15%

4.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-918

References

Timeline

Published: May 4, 2026
Last Modified: Jun 17, 2026
Status: Deferred

Frequently Asked Questions

What is CVE-2026-42140?

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.

How severe is CVE-2026-42140?

CVE-2026-42140 has a CVSS score of 4.4/10 (MEDIUM severity). The EPSS model estimates a 0.15% probability of exploitation in the next 30 days.

How do I fix CVE-2026-42140?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.