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Cross-site Scripting in ZenUML

Moderate severity GitHub Reviewed Published Jun 26, 2024 in mermaid-js/zenuml-core • Updated Jun 26, 2024

Package

npm @zenuml/core (npm)

Affected versions

< 3.23.25

Patched versions

3.23.25

Description

Summary

Markdown-based comments in the ZenUML diagram syntax are susceptible to Cross-site Scripting (XSS).

Details

The comment feature allows the user to attach small notes for reference. This feature allows the user to enter in their comment in markdown comment, allowing them to use common markdown features, such as ** for bolded text. However, the markdown text is currently not sanitized before rendering, allowing an attacker to enter a malicious payload for the comment which leads to XSS.

https://github.com/mermaid-js/zenuml-core/blob/dcfee8cde42673c09e19401f43ad8506658c8442/src/components/DiagramFrame/SeqDiagram/MessageLayer/Block/Statement/Comment/Comment.vue#L65

PoC

// p<img onerror=alert(1) src=""/>
A->B:hi

Above is a POC diagram payload that results in an XSS.

Here is a similar POC in mermaid.live: https://mermaid.live/edit#pako:eNpNjrFuwyAQhl8F3dRK1DaQGhs1kVq1Y6duFQsylwTVgEWw1MTyuxc5S7df39399y0wRIug4IZh9qMOdU2mF-dPJAZMKaa9GTHlB_ZILmnYa9BQH3R4fTq8qbMDCh6TN86WhkUHQjTkM3rUoEq0Jv2Ui7CWPTPn-HUNA6icZqQwT9ZkfHfmlIwHdTTjpVC0Lsf0eVfazChMJoBa4BdUL6uGC8n7TrCGd5zCFRRnXbVjvBVNK3gJXbtSuMVYSlnFC-Kyf961UshWbmXf2-y_xcf29c7WP2yrVC0

Impact

This puts existing applications that use ZenUML unsandboxed at risk of arbitrary JavaScript execution when rendering user-controlled diagrams.

References

@MrCoder MrCoder published to mermaid-js/zenuml-core Jun 26, 2024
Published to the GitHub Advisory Database Jun 26, 2024
Reviewed Jun 26, 2024
Published by the National Vulnerability Database Jun 26, 2024
Last updated Jun 26, 2024

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N

EPSS score

0.043%
(10th percentile)

Weaknesses

CVE ID

CVE-2024-38527

GHSA ID

GHSA-q6xv-jm4v-349h

Source code

Credits

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