How severe is CVE-2020-15164?

CVE-2020-15164 has a CVSS 3.x base score of 10.0, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.

Is CVE-2020-15164 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (64th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-15164?

CVE-2020-15164 affects Scratch-wiki Scratch Login. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-15164?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2020-15164 published?

CVE-2020-15164 was published on 2020-08-28 and last updated on 2026-06-17.

CVE-2020-15164

CVE-2020-15164 is a critical-severity vulnerability in Scratch-wiki Scratch Login with a CVSS 3.x base score of 10.0. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-74.

Key facts

Severity: Critical (CVSS 3.x base score 10.0)
CVSS v2: 6.4
EPSS exploit prediction: 1% (64th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-74
Affected product: Scratch-wiki Scratch Login
Published: 2020-08-28
Last modified: 2026-06-17

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.

Frequently asked questions

What is 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. 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.
How severe is CVE-2020-15164?: CVE-2020-15164 has a CVSS 3.x base score of 10.0, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.
Is CVE-2020-15164 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (64th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-15164?: CVE-2020-15164 affects Scratch-wiki Scratch Login. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-15164?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2020-15164 published?: CVE-2020-15164 was published on 2020-08-28 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:scratch-wiki:scratch_login:*:*:*:*:*:mediawiki:*:*

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