What’s Vulnerable › Vulnerabilities

CVE-2020-26121

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2020-09-27 · updated 2026-06-17
• Weakness: CWE-863

Description

An issue was discovered in the FileImporter extension for MediaWiki before 1.34.4. An attacker can import a file even when the target page is protected against "page creation" and the attacker should not be able to create it. This occurs because of a mishandled distinction between an upload restriction and a create restriction. An attacker cannot leverage this to overwrite anything, but can leverage this to force a wiki to have a page with a disallowed title.

Affected products

• Fedoraproject Fedora: 33
• Wikimedia Foundation MediaWiki: before 1.34.4 — fixed in 1.34.4

How to fix

Upgrade to a fixed version: Wikimedia Foundation MediaWiki 1.34.4. Check the vendor advisory for mitigations.

References

• https://commons.wikimedia.org/w/index.php?oldid=454609892#File:Wiki.png
• https://gerrit.wikimedia.org/r/q/Ib852a96afc4dca10516d0510e69c10f9892b351b
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RTTPZ7XMDS66I442OLLHXBDNP2LCBJU6/
• https://phabricator.wikimedia.org/T262628
• https://commons.wikimedia.org/w/index.php?oldid=454609892#File:Wiki.png
• https://gerrit.wikimedia.org/r/q/Ib852a96afc4dca10516d0510e69c10f9892b351b
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RTTPZ7XMDS66I442OLLHXBDNP2LCBJU6/
• https://phabricator.wikimedia.org/T262628

Get alerted when CVE-2020-26121 or the next vulnerability affects your stack