CVE-2026-0858: Plantuml Cross-Site Scripting Vulnerability

LOW
Advisory Identifier: GHSA-hrvf-g648-rf3m
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CVSS 6.1
CWE-79
Published
Advisory Summary

CVE-2026-0858 is a LOW (CVSS 6.1) cross-site scripting vulnerability (CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')) affecting Plantuml libraries in the Maven ecosystem. The issue involves plantuml is vulnerable to stored xss due to insufficient sanitization of interactive attributes in graphviz diagrams. Remediation is available by upgrading affected packages to version 1.2026.0.

CVE-2026-0858 at a Glance

CVE Identifier CVE-2026-0858
GHSA Identifier GHSA-hrvf-g648-rf3m
Severity LOW
CVSS v3.1 Base Score 6.1
CWE Classification CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Affected Product Plantuml
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 6.1

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction Required (UI:R)
Scope Changed (S:C)
Confidentiality Low (C:L)
Integrity Low (I:L)
Availability None (A:N)

How to Fix CVE-2026-0858

To remediate this vulnerability, upgrade all affected Plantuml dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

net.sourceforge.plantuml:plantuml fixed: 1.2026.0 
<dependency>
    <groupId>net.sourceforge.plantuml</groupId>
    <artifactId>plantuml</artifactId>
    <version>1.2026.0</version>
</dependency>
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

mvn dependency:tree -Dincludes=net.sourceforge.plantuml

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2026-0858, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree -Dincludes=net.sourceforge.plantuml

Analyze the terminal output to locate any version of Plantuml in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.2026.0), your application is affected.

Note: The mvn dependency:tree -Dincludes=net.sourceforge.plantuml command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting'), where the product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. In Plantuml, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

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.

CVE-2026-0858 Affected Plantuml Versions

1 component(s)
Fixed Versions:
1.2026.0
Product / Package Ecosystem Affected Versions Fixed Version
net.sourceforge.plantuml:plantuml
maven/net.sourceforge.plantuml/plantuml
Maven
< 1.2026.0
1.2026.0

References

NVD — CVE-2026-0858 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-0858
Security Fix Commit FIX COMMIT
https://github.com/plantuml/plantuml/commit/6826315db092d2e432aeab1a0894e08017c6e4bd
Plantuml Source Repository REPOSITORY
https://github.com/plantuml/plantuml
Plantuml Release RELEASE
https://github.com/plantuml/plantuml/releases/tag/v1.2026.0
Plantuml Security Information SECURITY
https://security.snyk.io/vuln/SNYK-JAVA-NETSOURCEFORGEPLANTUML-14552230

Frequently Asked Questions

What is CVE-2026-0858?
CVE-2026-0858 is a security vulnerability in Plantuml involving PlantUML is vulnerable to Stored XSS due to insufficient sanitization of interactive attributes in GraphViz diagrams under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting').
Which Plantuml versions are affected?
Affected versions include releases prior to 1.2026.0 across affected packages: net.sourceforge.plantuml:plantuml.
What version fixes CVE-2026-0858?
Upgrading to 1.2026.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is plantuml affected?
Yes, net.sourceforge.plantuml:plantuml is affected in releases prior to 1.2026.0. Upgrade your dependency to 1.2026.0 or later.
What is the CVSS score of CVE-2026-0858?
CVE-2026-0858 has a CVSS v3.1 base score of 6.1 (LOW) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.
What CWE is associated with CVE-2026-0858?
CVE-2026-0858 is classified under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.).
How can I check Maven dependencies for CVE-2026-0858?
Run the dependency tree command: 'mvn dependency:tree -Dincludes=net.sourceforge.plantuml'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-hrvf-g648-rf3m",
  "modified" : "2026-01-16T20:45:39Z",
  "published" : "2026-01-16T06:30:15Z",
  "aliases" : [ "CVE-2026-0858" ],
  "summary" : "PlantUML is vulnerable to Stored XSS due to insufficient sanitization of interactive attributes in GraphViz diagrams",
  "details" : "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.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:L/VA:N/SC:L/SI:L/SA:N/E:P"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "net.sourceforge.plantuml:plantuml"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.2026.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-0858"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/plantuml/plantuml/commit/6826315db092d2e432aeab1a0894e08017c6e4bd"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/plantuml/plantuml"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/plantuml/plantuml/releases/tag/v1.2026.0"
  }, {
    "type" : "WEB",
    "url" : "https://security.snyk.io/vuln/SNYK-JAVA-NETSOURCEFORGEPLANTUML-14552230"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-79" ],
    "severity" : "LOW",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-01-16T20:45:39Z",
    "nvd_published_at" : "2026-01-16T05:16:16Z"
  }
}