CVE-2020-27621

Name: CVE-2020-27621
Creator: NVD / NIST
Published: 2020-10-22T04:15:12.187+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 4.3/10EPSS 0.70%

Last modified Jun 17, 2026

CVE-2020-27621 is a medium-severity vulnerability rated 4.3/10 on the CVSS scale. The FileImporter extension in MediaWiki through 1.35.0 was not properly attributing various user actions to a specific user's IP address. Instead, for various actions, it would report the IP address of an internal Wikimedia Foundation server by omitting X-Forwarded-For data. EPSS estimates a 0.70% chance of exploitation in the next 30 days.

Description

The FileImporter extension in MediaWiki through 1.35.0 was not properly attributing various user actions to a specific user's IP address. Instead, for various actions, it would report the IP address of an internal Wikimedia Foundation server by omitting X-Forwarded-For data. This resulted in an inability to properly audit and attribute various user actions performed via the FileImporter extension.

Metrics

CVSS 3.1

4.3/10

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

EPSS Probability

0.70%

48.4th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Vendor	Product	Versions
Mediawiki	Mediawiki	<= 1.35.0

References

https://gerrit.wikimedia.org/r/q/I24a240253c7a5c66dd493a68e8c23d95a17e1b21Exploit, Patch, Vendor Advisory
https://phabricator.wikimedia.org/T265810Exploit, Patch, Vendor Advisory
https://gerrit.wikimedia.org/r/q/I24a240253c7a5c66dd493a68e8c23d95a17e1b21Exploit, Patch, Vendor Advisory
https://phabricator.wikimedia.org/T265810Exploit, Patch, Vendor Advisory

Timeline

Published: Oct 22, 2020
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-27621?

How severe is CVE-2020-27621?

CVE-2020-27621 has a CVSS score of 4.3/10 (MEDIUM severity). The EPSS model estimates a 0.70% probability of exploitation in the next 30 days.

How do I fix CVE-2020-27621?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2020-27621?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST