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org.xwiki.contrib.markdown:syntax-markdown-commonmark12 vulnerable to XSS via Markdown content

Critical severity GitHub Reviewed Published Apr 30, 2025 in xwiki-contrib/syntax-markdown • Updated May 1, 2025

Package

maven org.xwiki.contrib.markdown:syntax-markdown-commonmark12 (Maven)

Affected versions

>= 8.2, < 8.9

Patched versions

8.9

Description

Impact

The Markdown syntax is vulnerable to XSS through HTML. In particular, using Markdown syntax, it's possible for any user to embed Javascript code that will then be executed on the browser of any other user visiting either the document or the comment that contains it. In the instance that this code is executed by a user with admins or programming rights, this issue compromises the confidentiality, integrity and availability of the whole XWiki installation.

To reproduce, on an instance where the CommonMark Markdown Syntax 1.2 extension is installed, log in as a user without script rights. Edit a document and set its syntax to Markdown. Then , add the content <script>alert("XSS")</script> and refresh the page. If an alert appears containing "XSS", then the instance is vulnerable.

Patches

This has been patched in version 8.9 of the CommonMark Markdown Syntax 1.2 extension.

Workarounds

We're not aware of any workaround except upgrading.

References

References

@tmortagne tmortagne published to xwiki-contrib/syntax-markdown Apr 30, 2025
Published to the GitHub Advisory Database Apr 30, 2025
Reviewed Apr 30, 2025
Published by the National Vulnerability Database Apr 30, 2025
Last updated May 1, 2025

Severity

Critical

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
Low
Privileges required
Low
User interaction
Required
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

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:L/PR:L/UI:R/S:C/C:H/I:H/A:H

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(11th percentile)

Weaknesses

CVE ID

CVE-2025-46558

GHSA ID

GHSA-8g2j-rhfh-hq3r

Source code

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