What’s Vulnerable › Vulnerabilities

CVE-2020-15164: Authentication Bypass in Scratch Login (mediawiki-scratch-login)

• Severity: critical (CVSS 10.0 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2020-08-28 · updated 2026-06-17
• Weakness: CWE-287

Description

in Scratch Login (MediaWiki extension) before version 1.1, any account can be logged into by using the same username with leading, trailing, or repeated underscore(s), since those are treated as whitespace and trimmed by MediaWiki. This affects all users on any wiki using this extension. Since version 1.1, comments by users whose usernames would be trimmed on MediaWiki are ignored when searching for the verification code.

Affected products

• InternationalScratchWiki mediawiki-scratch-login: before 1.1 — fixed in 1.1

How to fix

Upgrade to a fixed version: InternationalScratchWiki mediawiki-scratch-login 1.1. Check the vendor advisory for mitigations.

References

• https://github.com/InternationalScratchWiki/mediawiki-scratch-login/commit/70849ef375016a1061490c8c4744046dbfc3e679
• https://github.com/InternationalScratchWiki/mediawiki-scratch-login/security/advisories/GHSA-8fq5-g4m5-6j43
• https://github.com/InternationalScratchWiki/mediawiki-scratch-login/commit/70849ef375016a1061490c8c4744046dbfc3e679
• https://github.com/InternationalScratchWiki/mediawiki-scratch-login/security/advisories/GHSA-8fq5-g4m5-6j43

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