Bug 1909227 (CVE-2020-35474)

Summary: CVE-2020-35474 mediawiki: message recentchanges-legend-watchlistexpiry can contain raw html
Product: [Other] Security Response Reporter: Guilherme de Almeida Suckevicz <gsuckevi>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED WONTFIX QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: aos-bugs, axel.thimm, bmontgom, eparis, jburrell, jokerman, mike, nstielau, puiterwijk, shurley, sponnaga
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: mediawiki 1.31.11, mediawiki 1.35.1 Doc Type: If docs needed, set a value
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2021-10-28 02:58:47 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 1909228, 1910209    
Bug Blocks: 1909242    

Description Guilherme de Almeida Suckevicz 2020-12-18 16:52:46 UTC 
In MediaWiki before 1.35.1, the combination of Html::rawElement and Message::text leads to XSS because the definition of MediaWiki:recentchanges-legend-watchlistexpiry can be changed onwiki so that the output is raw HTML.

References:
https://phabricator.wikimedia.org/T268894
https://lists.wikimedia.org/pipermail/mediawiki-announce/2020-December/000268.html
Comment 1 Guilherme de Almeida Suckevicz 2020-12-18 16:53:02 UTC 
Created mediawiki tracking bugs for this issue:

Affects: fedora-all [bug 1909228]
Comment 3 Sam Fowler 2020-12-23 06:26:03 UTC 
External References:

https://lists.wikimedia.org/pipermail/mediawiki-announce/2020-December/000268.html