Debian LTS: Security Advisory for mediawiki (DLA-2648-1)

The remote host is missing an update for the 'mediawiki' package(s) announced via the DLA-2648-1 advisory.

Several vulnerabilities were discovered in mediawiki, a wiki website engine for collaborative work. 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.

'mediawiki' package(s) on Debian Linux.

Checks if a vulnerable package version is present on the target host.

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.