CVE-2020-15164
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.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (1.17%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 3.1
- 10.0 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N
- EPSS
- 1.17% probability · 67th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-287, CWE-74
- Affected
- scratch-wiki/scratch login
- Source
- security-advisories@github.com
EPSS 1.2% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://github.com/InternationalScratchWiki/mediawiki-scratch-login/commit/70849ef375016a1061490c8c4744046dbfc3e679Patch, Third Party Advisory
- https://github.com/InternationalScratchWiki/mediawiki-scratch-login/security/advisories/GHSA-8fq5-g4m5-6j43Third Party Advisory
- https://github.com/InternationalScratchWiki/mediawiki-scratch-login/commit/70849ef375016a1061490c8c4744046dbfc3e679Patch, Third Party Advisory
- https://github.com/InternationalScratchWiki/mediawiki-scratch-login/security/advisories/GHSA-8fq5-g4m5-6j43Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.