Debian 9: DLA-2648-1 Moderate: MediaWiki Denial of Service

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