What is CVE-2021-45471?

CVE-2021-45471 is a medium-severity vulnerability in MediaWiki. CVSS score: 5.3/10. Published 2021-12-24.

How severe is CVE-2021-45471?

Medium severity. CVSS v3 base score is 5.3 out of 10.

Vulnerability in MediaWiki

CVE-2021-45471

In MediaWiki through 1.37, blocked IP addresses are allowed to edit EntitySchema items.

Published 2021-12-24 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N.

EPSS exploit prediction

EPSS: 0.012 (68.1th percentile), scored 2026-10-02.

Low probability of exploitation in the next 30 days, but still tracked. 68th percentile — 68.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.012 · newest: 0.012 · change: 0.000

Affected products

MediaWiki
Fedoraproject Fedora — versions 35

References

phabricator.wikimedia.org/T296578 (Third Party Advisory)
gerrit.wikimedia.org/r/q/Iac86cf63bd014ef99e83dccfce9b8942e15d2bf9 (Third Party Advisory)
gerrit.wikimedia.org/r/q/Id9af124427bcd1e85301d2140a38bf47bbc5622c (Third Party Advisory)
lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (vendor-advisory)

Frequently asked questions

What is CVE-2021-45471?: CVE-2021-45471 is a medium-severity vulnerability in MediaWiki. CVSS score: 5.3/10. Published 2021-12-24.
How severe is CVE-2021-45471?: Medium severity. CVSS v3 base score is 5.3 out of 10.