How severe is CVE-2021-31549?

CVE-2021-31549 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.

Is CVE-2021-31549 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (52nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-31549?

CVE-2021-31549 affects Mediawiki. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-31549?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-31549 published?

CVE-2021-31549 was published on 2021-04-22 and last updated on 2026-06-17.

CVE-2021-31549

CVE-2021-31549 is a medium-severity vulnerability in Mediawiki with a CVSS 3.x base score of 4.3. 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-200.

Key facts

Severity: Medium (CVSS 3.x base score 4.3)
CVSS v2: 4.0
EPSS exploit prediction: 1% (52nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-200
Affected product: Mediawiki
Published: 2021-04-22
Last modified: 2026-06-17

Description

An issue was discovered in the AbuseFilter extension for MediaWiki through 1.35.2. The Special:AbuseFilter/examine form allowed for the disclosure of suppressed MediaWiki usernames to unprivileged users.

Frequently asked questions

What is CVE-2021-31549?: An issue was discovered in the AbuseFilter extension for MediaWiki through 1.35.2. The Special:AbuseFilter/examine form allowed for the disclosure of suppressed MediaWiki usernames to unprivileged users.
How severe is CVE-2021-31549?: CVE-2021-31549 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.
Is CVE-2021-31549 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (52nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-31549?: CVE-2021-31549 affects Mediawiki. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-31549?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-31549 published?: CVE-2021-31549 was published on 2021-04-22 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:mediawiki:mediawiki:*:*:*:*:*:*:*:*

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