What’s Vulnerable › Vulnerabilities

CVE-2020-35477

• Severity: medium (CVSS 5.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.7% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2020-12-18 · updated 2026-06-17
• Weakness: CWE-670

Description

MediaWiki before 1.35.1 blocks legitimate attempts to hide log entries in some situations. If one sets MediaWiki:Mainpage to Special:MyLanguage/Main Page, visits a log entry on Special:Log, and toggles the "Change visibility of selected log entries" checkbox (or a tags checkbox) next to it, there is a redirection to the main page's action=historysubmit (instead of the desired behavior in which a revision-deletion form appears).

Affected products

• Debian Linux: 9.0, 10.0
• Fedoraproject Fedora: 33
• Wikimedia Foundation MediaWiki: before 1.35.1 — fixed in 1.35.1

How to fix

Upgrade to a fixed version: Wikimedia Foundation MediaWiki 1.35.1. Check the vendor advisory for mitigations.

References

• https://lists.debian.org/debian-lts-announce/2020/12/msg00034.html
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/STT5Z4A3BCXVH3WIPICWU2FP4IPIMUPC/
• https://lists.wikimedia.org/pipermail/mediawiki-announce/2020-December/000268.html
• https://phabricator.wikimedia.org/T205908
• https://www.debian.org/security/2020/dsa-4816
• https://lists.debian.org/debian-lts-announce/2020/12/msg00034.html
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/STT5Z4A3BCXVH3WIPICWU2FP4IPIMUPC/
• https://lists.wikimedia.org/pipermail/mediawiki-announce/2020-December/000268.html
• https://phabricator.wikimedia.org/T205908
• https://www.debian.org/security/2020/dsa-4816

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