CVE-2026-0858Network attack vector

Stored script execution via GraphViz SVG export

Published Jan 16, 2026 · Updated Jan 16, 2026

Stored XSS in PlantUML before 1.2026.0 allows remote attackers to execute script through crafted GraphViz diagrams rendered as SVG. PSystemDot's SVG export passes attacker-controlled DOT to GraphViz after regex filters strip only selected schemes, tags, attributes, and event-handler syntax. Exploitation requires an application to generate the SVG from untrusted diagram text and a user to open or render the output in a script-capable context.

CVSS severity6.1
Medium
EPSS probability0.34%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in PlantUML before 1.2026.0 allows remote attackers to execute script through crafted GraphViz diagrams rendered as SVG. PSystemDot's SVG export passes attacker-controlled DOT to GraphViz after regex filters strip only selected schemes, tags, attributes, and event-handler syntax. Exploitation requires an application to generate the SVG from untrusted diagram text and a user to open or render the output in a script-capable context.

The record

CVE
CVE-2026-0858
Published
Jan 16, 2026
Updated
Jan 16, 2026
Vendor
PlantUML
Product
PlantUML
Classifications
CWE-79, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 16, 2026CVE publishedPublication date reported by the CVE source.
  2. Jan 16, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <1.2026.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

PlantUML · PlantUMLversion=0 <1.2026.0

Published CVSS scores

6.1SnykCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
2.0SnykCVSS: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
5.1SnykCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:L/VA:N/SC:L/SI:L/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1203Exploitation for Client Execution

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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