Skip to content
Fencer Intel
medium 5.4

CVE-2021-31552 json

An issue was discovered in the AbuseFilter extension for MediaWiki through 1.35.2.

published 5y ago modified 4mo ago also BIT-mediawiki-2021-31552 , EUVD-2021-18449

cvss
5.4
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 47%
public exploits
0
none known

Summary

An issue was discovered in the AbuseFilter extension for MediaWiki through 1.35.2. It incorrectly executed certain rules related to blocking accounts after account creation. Such rules would allow for user accounts to be created while blocking only the IP address used to create an account (and not the user account itself). Such rules could also be used by a nefarious, unprivileged user to catalog and enumerate any number of IP addresses related to these account creations.

Patch / fix

  • bitnami mediawiki 1.35.3

Is CVE-2021-31552 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

Check with Fencer

Exploit prediction

0.58% chance of exploitation in the next 30 days, higher than 47% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
NVD 3.1 5.4 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
NVD 2.0 5.5 AV:N/AC:L/Au:S/C:P/I:P/A:N
OSV 3.1 5.4 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N

Affected packages

ecosystem package affected fixed in
bitnami mediawiki
<1.35.3
1.35.3

Classification

Weakness

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.