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Debian LTS Advisory DLA-2648-1                [email protected]
https://www.debian.org/lts/security/                          Abhijith PA
May 05, 2021                                  https://wiki.debian.org/LTS
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Package        : mediawiki
Version        : 1:1.27.7-1~deb9u8
CVE ID         : CVE-2021-20270 CVE-2021-27291 CVE-2021-30152 
                 CVE-2021-30155 CVE-2021-30158 CVE-2021-30159
Debian Bug     : 985574 984664

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.

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/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