CVE-2021-31553

mediumpriority · track · 26EPSS 0.014 · 72 %ileEUUS

grimoire priorityP3 · Track

Exploitable?

—

no known exploitation

Likely / severe?

1.40% (72nd) EPSS

CVSS 6.4 · medium

Is it mine?

3 products

Check your exposure

Who says so?

4 sources

cnnvd · enisa_euvd · nvd · osv

EPSS · scored 2026-10-24

An issue was discovered in the CheckUser extension for MediaWiki through 1.35.2. MediaWiki usernames with trailing whitespace could be stored in the cu_log database table such that denial of service occurred for certain CheckUser extension pages and functionality. For example, the attacker could turn off Special:CheckUserLog and thus interfere with usage tracking.

cvss

Technical severity, 0–10. One row per scoring source.

6.5

010

base score 0–10 · higher = more severe · hover a vector to decode

v2.06.4mediumAV:N/AC:L/Au:N/C:N/I:P/A:Pprimary · NVD / NIST USexploitability 10 · impact 4.9

v3.16.5mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:Lprimary · NVD / NIST USexploitability 3.9 · impact 2.5

v3.16mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L/E:Usecondary · CVSS-BT (t0sche)

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-428USprimary

affected products (3)

Products and version ranges known to be affected.

n/a n/a≤ n/aenisa_euvdEU
mediawiki mediawiki≤ 1.35.2nvdUScpe:2.3:a:mediawiki:mediawiki:*:*:*:*:*:*:*:*
Bitnami mediawiki< 1.35.3osvUSpkg:bitnami/mediawiki

advisories (1)

Vendor and ecosystem advisories describing this.

BIT-mediawiki-2021-315532024-03-06vendor · osvUS
An issue was discovered in the CheckUser extension for MediaWiki through 1.35.2. MediaWiki usernames with trailing whitespace could be stored in the cu_log database table such that denial of service occurred for certain CheckUser extension pages and functionality. For example, the attacker could turn off Special:CheckUserLog and thus interfere with usage tracking.

also known as (3)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd nvd osv NVD CVE.org MITRE

published 2021-04-22modified 2026-06-17

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+472 more

references (23)

External citations — patches, advisories, analysis.

scry

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