CVE-2021-31554

MEDIUMNVD 5.45.4—

5.4

An issue was discovered in the AbuseFilter extension for MediaWiki through 1.35.2. It improperly handled account blocks for certain automatically created MediaWiki user accounts, thus allowing nefarious users to remain unblocked.

CVSS v3: 5.4
EG Score: 5.4(medium)
EPSS: 25.9%
KEV: Not listed

Published

April 22, 2021

Last Modified

November 21, 2024

References (4)

cve@mitrehttps://gerrit.wikimedia.org/r/q/Ie1f4333d5b1c9d17fb2236fe38a31de427a4cc48
cve@mitrehttps://phabricator.wikimedia.org/T272244
af854a3a-2127-422b-91ae-364da2661108https://gerrit.wikimedia.org/r/q/Ie1f4333d5b1c9d17fb2236fe38a31de427a4cc48
af854a3a-2127-422b-91ae-364da2661108https://phabricator.wikimedia.org/T272244

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 12× in last 7d / 20× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

2026-06-08 14:15 UTCEPSS rescore
2026-06-07 15:23 UTCEPSS rescore
2026-06-07 15:23 UTCEPSS rescore
2026-06-06 13:46 UTCEPSS rescore
2026-06-06 13:46 UTCEPSS rescore
2026-06-06 13:46 UTCEPSS rescore
2026-06-05 22:45 UTCEPSS rescore
2026-06-05 22:45 UTCEPSS rescore
2026-06-05 06:09 UTCEPSS rescore
2026-06-05 06:09 UTCEPSS rescore
2026-06-04 13:10 UTCEPSS rescore
2026-06-04 13:10 UTCEPSS rescore
2026-06-02 20:11 UTCEPSS rescore
2026-06-02 20:11 UTCEPSS rescore
2026-06-02 20:11 UTCEPSS rescore
2026-06-01 13:50 UTCEPSS rescore
2026-06-01 13:50 UTCEPSS rescore
2026-05-31 22:29 UTCEPSS rescore
2026-05-31 22:29 UTCEPSS rescore
2026-05-29 13:42 UTCEPSS rescore

Frequently asked(5)

What is CVE-2021-31554?

CVE-2021-31554 is a medium vulnerability published on April 22, 2021. An issue was discovered in the AbuseFilter extension for MediaWiki through 1.35.2. It improperly handled account blocks for certain automatically created MediaWiki user accounts, thus allowing nefarious users to remain unblocked.

When was CVE-2021-31554 disclosed?

CVE-2021-31554 was first published in the National Vulnerability Database on April 22, 2021, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.

Is CVE-2021-31554 actively exploited?

CVE-2021-31554 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 25.9% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.

What is the CVSS score of CVE-2021-31554?

CVE-2021-31554 has a CVSS v3 base score of 5.4 (NVD).

How do I remediate CVE-2021-31554?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-31554, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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CVE-2021-31554

📅 Published

🔄 Last Modified

🔗 References (4)

Weakness Classification(2)

Data Freshness Timeline

❓ Frequently asked(5)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2021-31554?

🔗 Related CVEs(same CWE)

Same CWE

Published

Last Modified

References (4)

Frequently asked(5)

Related CVEs(same CWE)