CVE-2020-35623

Name: CVE-2020-35623
Creator: NVD / NIST
Published: 2020-12-21T23:15:12.437+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 1.08%

Last modified Jun 17, 2026

CVE-2020-35623 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. An issue was discovered in the CasAuth extension for MediaWiki through 1.35.1. Due to improper username validation, it allowed user impersonation with trivial manipulations of certain characters within a given username. EPSS estimates a 1.08% chance of exploitation in the next 30 days.

Description

An issue was discovered in the CasAuth extension for MediaWiki through 1.35.1. Due to improper username validation, it allowed user impersonation with trivial manipulations of certain characters within a given username. An ordinary user may be able to login as a "bureaucrat user" who has a similar username, as demonstrated by usernames that differ only in (1) bidirectional override symbols or (2) blank space.

Metrics

CVSS 3.1

7.5/10

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

EPSS Probability

1.08%

60.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Mediawiki	Mediawiki	<= 1.35.1

References

https://github.com/CWRUChielLab/CASAuth/pull/11Patch, Third Party Advisory
https://phabricator.wikimedia.org/T263498Exploit, Third Party Advisory
https://github.com/CWRUChielLab/CASAuth/pull/11Patch, Third Party Advisory
https://phabricator.wikimedia.org/T263498Exploit, Third Party Advisory

Timeline

Published: Dec 21, 2020
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-35623?

How severe is CVE-2020-35623?

CVE-2020-35623 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 1.08% probability of exploitation in the next 30 days.

How do I fix CVE-2020-35623?

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-2020-35623?

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

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Source: NVD / NIST