Several vulnerabilities were discovered in mediawiki, a wiki
website engine for collaborative work.
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.
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.
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.
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.
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.
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
We recommend that you upgrade your mediawiki packages.
For the detailed security status of mediawiki please refer to
its security tracker page at:
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
Debian LTS Advisory DLA-2648-1 [email protected]
https://www.debian.org/lts/security/ Abhijith PA
May 05, 2021 https://wiki.debian.org/LTS
Version : 1:1.27.7-1~deb9u8
CVE-2021-30155 CVE-2021-30158 CVE-2021-30159