What is CVE-2021-31546?

CVE-2021-31546 is a medium-severity vulnerability in MediaWiki, classified under Insertion of Sensitive Information into Log File. CVSS score: 4.3/10. Published 2021-04-22.

How severe is CVE-2021-31546?

Medium severity. CVSS v3 base score is 4.3 out of 10.

Information disclosure in MediaWiki

CVE-2021-31546

An issue was discovered in the AbuseFilter extension for MediaWiki through 1.35.2. It incorrectly logged sensitive suppression deletions, which should not have been visible to users with access to view AbuseFilter log data.

Published 2021-04-22 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N.

EPSS exploit prediction

EPSS: 0.007 (52.1th percentile), scored 2026-10-01.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 52nd percentile — 52.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: 0.000

Affected products

MediaWiki

Weakness classification (CWE)

CWE-532 — Insertion of Sensitive Information into Log File

References

phabricator.wikimedia.org/T71617 (Third Party Advisory)
gerrit.wikimedia.org/r/q/I38a0a24fa32ca7a052b6940864a32b3856e84553 (Third Party Advisory, Issue Tracking)

Frequently asked questions

What is CVE-2021-31546?: CVE-2021-31546 is a medium-severity vulnerability in MediaWiki, classified under Insertion of Sensitive Information into Log File. CVSS score: 4.3/10. Published 2021-04-22.
How severe is CVE-2021-31546?: Medium severity. CVSS v3 base score is 4.3 out of 10.