Greetings-

With the security/maintenance release of MediaWiki 1.31.13/1.35.2 [0], we would also like to provide this supplementary announcement of MediaWiki extensions and skins with now-public Phabricator tasks, security patches and backports [1]:

== CommentBox ==
+ (T270767, CVE-2021-31550) - Wg variables aren't validated by CommentBox - possible raw html insertion risk
<https://gerrit.wikimedia.org/r/651934>

== AbuseFilter ==
+ (T272333, CVE-2021-31548) - Disallow the edit if blocking the user didn't succeed
<https://gerrit.wikimedia.org/r/657092>

== WikiLove ==
+ (T270142, CVE-2021-31557) - mw.config.get( 'wikilove-anon' ) leaks the existence of hidden users
<https://gerrit.wikimedia.org/r/q/Ibcd87abe01719222beadcfc0de13038c3021adef>

== PageForms ==
+ (T259433, CVE-2021-31551) - XSS issue in Extension:PageForms
<https://gerrit.wikimedia.org/r/q/I5e0abbc2f80e6bda255b3b32a4df39a7fe7d3793>
<https://gerrit.wikimedia.org/r/q/Ibe68b070ee791cd0c8e7f50eb04ac4e066b1512c>
<https://gerrit.wikimedia.org/r/q/I20b63bd38779d2ccbe2d86f9879df85ca3b685f6>

== AbuseFilter ==
+ (T71617, CVE-2021-31546) - AbuseFilter logs suppression deletions
<https://gerrit.wikimedia.org/r/q/I38a0a24fa32ca7a052b6940864a32b3856e84553>

== AbuseFilter ==
+ (T223654, CVE-2021-31547) - AbuseFilterCheckMatch API reveals suppressed edits and usernames
<https://gerrit.wikimedia.org/r/q/I4900b1be73323599d74e3164447f81eded094d75>
<https://gerrit.wikimedia.org/r/q/I3f7dbd8b873d411e37c8c3aac2339bf5ec36907d>

== AbuseFilter ==
+ (T71367, CVE-2021-31545) - page_recent_contributors leaks revdeleted user names
<https://gerrit.wikimedia.org/r/q/I8d5ed9ca84282ee50832035af86123633fc88293>

== AbuseFilter ==
+ (T274152, CVE-2021-31549) - Special:AbuseFilter/examine reveals suppressed usernames
<https://gerrit.wikimedia.org/r/q/I6063c02fa261c4cc0e6dbbb2db4e111eb85912c2>
<https://gerrit.wikimedia.org/r/q/I71a6d521bd12931ce60eec4d2dc35af19146000f>

== CheckUser ==
+ (T275669, CVE-2021-31553) - Checkuser stores users to cu_log with trailing spaces, allowing all CUs to turn off Special:CheckuserLog at will
<https://gerrit.wikimedia.org/r/666963>
<https://gerrit.wikimedia.org/r/666964>

== AbuseFilter ==
+ (T152394, CVE-2021-31552) - AbuseFilter privacy concerns on action == 'createaccount' and 'accountname'
<https://gerrit.wikimedia.org/r/q/I8bae477ad7e4d0190335363ac2decf28e4313da1>

== AbuseFilter ==
+ (T272244, CVE-2021-31554) - AbuseFilter blocks not working for account autocreations
<https://gerrit.wikimedia.org/r/q/Ie1f4333d5b1c9d17fb2236fe38a31de427a4cc48>

== OAuth ==
+ (T277380, CVE-2021-31556) - OAuth doesn't validate length of oarc_rsa_key
<https://gerrit.wikimedia.org/r/q/I13ff0350a9a0a3cd5ab3e1f82dd0d8d9c13cf9e9>

== OAuth ==
+ (T277388, CVE-2021-31555) - OAuth doesn't validate length of oarc_version
<https://gerrit.wikimedia.org/r/q/I222c053b4b14ac1ad0f5b3a51565b1b9cd4c139d>

The Wikimedia Security Team recommends updating these extensions and/or skins to the current master branch or relevant, supported release branch [2] as soon as possible. Some of the referenced Phabricator tasks above _may_ still be private. Unfortunately, when security issues are reported, sometimes sensitive information is exposed and since Phabricator is historical, we cannot make these tasks public without exposing this sensitive information. If you have any additional questions or concerns regarding this update, please feel free to contact security@wikimedia.org or file a security task within Phabricator [3].

[0] https://lists.wikimedia.org/pipermail/mediawiki-announce/2021-April/000272.html
[1] https://phabricator.wikimedia.org/T270466
[2] https://www.mediawiki.org/wiki/Version_lifecycle
[3] https://www.mediawiki.org/wiki/Reporting_security_bugs

--
Scott Bassett