CVE-2026-0858 PlantUML is vulnerable to Stored XSS due to insufficient sanitization of interactive attributes in GraphViz diagrams
Attackers can inject malicious JavaScript into PlantUML diagrams, leading to arbitrary script execution in applications rendering the SVG output.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-0858?
CVE-2026-0858 is a medium-severity cross-site scripting vulnerability in net.sourceforge.plantuml:plantuml, published on 16 Jan 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
Versions of the package net.sourceforge.plantuml:plantuml before 1.2026.0 are vulnerable to Stored XSS due to insufficient sanitization of interactive attributes in GraphViz diagrams. As a result, a crafted PlantUML diagram can inject malicious JavaScript into generated SVG output, leading to arbitrary script execution in the context of applications that render the SVG.
Weakness: CWE-79
Which versions are affected by CVE-2026-0858?
2 open source packages ship an affected version, including net.sourceforge.plantuml:plantuml. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
net.sourceforge.plantuml:plantuml Maven | All versions | 1.2026.0 |
net.sourceforge.plantuml:plantuml Maven | All versions | 1.2026.0 |
Products include Plantuml Plantuml.
How do I fix CVE-2026-0858?
Upgrade net.sourceforge.plantuml:plantuml to 1.2026.0 or later.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-0858 being exploited?
There is no known exploitation of CVE-2026-0858 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-0858, GHSA-hrvf-g648-rf3m, UBUNTU-CVE-2026-0858.