In MediaWiki before 1.35.1, the messages userrights-expiry-current and userrights-expiry-none can contain raw HTML. XSS can happen when a user visits Special:UserRights but does not have rights to change all userrights, and the table on the left side has unchangeable groups in it. (The right column with the changeable groups is not affected and is escaped correctly.)

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - In MediaWiki before 1.35.1, the messages userrights-expiry-current and userrights-expiry-none can contain     raw HTML. XSS can happen when a user visits Special:UserRights but does not have rights to change all     userrights, and the table on the left side has unchangeable groups in it. (The right column with the     changeable groups is not affected and is escaped correctly.) (CVE-2020-35475)

Note that Nessus relies on the presence of the package as reported by the vendor.

https://lists.wikimedia.org/pipermail/mediawiki-announce/2020-December /000268.html

Note that Tenable Network Security has extracted the preceding description block directly from the Fedora update system website.
Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

Multiple security issues were discovered in MediaWiki, a website engine for collaborative work, which could result in cross-site scripting or the disclosure of hidden users.

ID	Name	Product	Family	Severity
245066	Linux Distros Unpatched Vulnerability : CVE-2020-35475	Nessus	Misc.	high
144618	Fedora 33 : mediawiki (2020-0be2d40e13)	Nessus	Fedora Local Security Checks	high
144477	Debian DSA-4816-1 : mediawiki - security update	Nessus	Debian Local Security Checks	high

Detections

Analytics

CVE-2020-35475

high

Tenable Plugins

high

high

high