Debian LTS: DLA-2648-1: mediawiki security update
Summary
CVE-2021-20270
An infinite loop in SMLLexer in Pygments used by mediawiki as
one if its lexers may lead to denial of service when performing
syntax highlighting of a Standard ML (SML) source file, as
demonstrated by input that only contains the "exception" keyword.
CVE-2021-27291
pygments, the lexers used by mediawiki rely heavily on regular
expressions. Some of the regular expressions have exponential or
cubic worst-case complexity and are vulnerable to ReDoS. By
crafting malicious input, an attacker can cause a denial of service.
CVE-2021-30152
An issue was discovered in MediaWiki. When using the MediaWiki
API to "protect" a page, a user is currently able to protect to a
higher level than they currently have permissions for.
CVE-2021-30155
An issue was discovered in MediaWiki before. ContentModelChange
does not check if a user has correct permissions to create and set
the content model of a nonexistent page.
CVE-2021-30158
An issue was discovered in MediaWiki. Blocked users are unable to
use Special:ResetTokens. This has security relevance because a
blocked user might have accidentally shared a token, or might know
that a token has been compromised, and yet is not able to block
any potential future use of the token by an unauthorized party.
CVE-2021-30159
An issue was discovered in MediaWiki. Users can bypass intended
restrictions on deleting pages in certain "fast double move"
situations. MovePage::isValidMoveTarget() uses FOR UPDATE, but
it's only called if Title::getArticleID() returns non-zero with no
special flags. Next, MovePage::moveToInternal() will delete the
page if getArticleID(READ_LATEST) is non-zero. Therefore, if the
page is missing in the replica DB, isValidMove() will return true,
and then moveToInternal() will unconditionally delete the page if
it can be found in the master.
For Debian 9 stretch, these problems have been fixed in version
1:1.27.7-1~deb9u8.
We recommend that you upgrade your mediawiki packages.
For the detailed security status of mediawiki please refer to
its security tracker page at:
https://security-tracker.debian.org/tracker/source-package/mediawiki
Further information about Debian LTS security advisories, how to apply
these updates to your system and frequently asked questions can be
found at: https://wiki.debian.org/LTS
