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XSS with Markdown rendering

High
haraldschilly published GHSA-8w44-hggw-p5rf May 28, 2024

Package

No package listed

Affected versions

< 419862a9c9879c

Patched versions

>= 419862a9c9879c

Description

Summary

Markdown allows <script> tags that execute when published.

PoC

markdown file:

<script>alert(1)</script>

publish the file.

example poc:
https://cocalc.com/share/public_paths/cce1c32004d0605bb8b6e84cdc83cb9b6eb99eaf

Severity

High

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
Unchanged
Confidentiality
High
Integrity
High
Availability
Low

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:U/C:H/I:H/A:L

CVE ID

CVE-2024-36109

Weaknesses

Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)

The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes special characters such as <, >, and & that could be interpreted as web-scripting elements when they are sent to a downstream component that processes web pages. Learn more on MITRE.

Credits