CVE-2021-31552
An issue was discovered in the AbuseFilter extension for MediaWiki through 1.35.2. It incorrectly...
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
Exploit likelihood
What each source reports
NVD Score used
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.
- Record
CVE-2021-31552- CVSS 3.1
- 5.4 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N - CVSS 2.0
- 5.5 Medium
AV:N/AC:L/Au:S/C:P/I:P/A:N - Weakness
- CWE-863
- Updated
- 2026-11-02
CVE List No score
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.
- Record
CVE-2021-31552- Updated
- 2026-11-02
EUVDEUVD-2021-18449 No score
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.
- Record
EUVD-2021-18449- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-gq3q-wc77-8wxx
An issue was discovered in the AbuseFilter extension for MediaWiki through 1.35.2. It incorrectly...
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.
- Record
GHSA-gq3q-wc77-8wxx- CVSS 3.1
- 5.4 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N - Weakness
- CWE-668
- Updated
- 2026-11-02
OSV
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.
- Record
CVE-2021-31552- CVSS 3.1
- 5.4 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N - Updated
- 2026-11-02
OSVBIT-mediawiki-2021-31552 No score
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.
- Record
BIT-mediawiki-2021-31552- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
mediawikiBitnami |
before 1.35.3 | 1.35.3 |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-31552 is a medium vulnerability (CVSS 5.4) in Mediawiki, published April 22, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.58%, the 47th percentile. Fixed in mediawiki 1.35.3.