CVE-2025-53478
CheckUser: Reflected Cross-Site Scripting (XSS) in Special:Investigate via unsanitized i18n messages
The CheckUser extension’s Special:Investigate interface is vulnerable to reflected XSS due to improper escaping of certain internationalized system messages rendered on the “IPs and User agents” tab.
This issue affects Mediawiki - CheckUser extension: from 1.39.X before 1.39.13, from 1.42.X before 1.42.7, from 1.43.X before 1.43.2.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- Required
What an attacker can affect
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
CheckUser: Reflected Cross-Site Scripting (XSS) in Special:Investigate via unsanitized i18n messages
The CheckUser extension’s Special:Investigate interface is vulnerable to reflected XSS due to improper escaping of certain internationalized system messages rendered on the “IPs and User agents” tab.
This issue affects Mediawiki - CheckUser extension: from 1.39.X before 1.39.13, from 1.42.X before 1.42.7, from 1.43.X before 1.43.2.
- Record
CVE-2025-53478- CVSS 3.1
- 5.4 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
EUVDEUVD-2025-20294
The CheckUser extension’s Special:Investigate interface is vulnerable to reflected XSS due to improper escaping of certain internationalized system messages rendered on the “IPs and User agents” tab.
This issue affects Mediawiki - CheckUser extension: from 1.39.X before 1.39.13, from 1.42.X before 1.42.7, from 1.43.X before 1.43.2.
- Record
EUVD-2025-20294- CVSS 3.1
- 5.4 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-r979-wmj9-cr9m
The CheckUser extension’s Special:Investigate interface is vulnerable to reflected XSS due to...
The CheckUser extension’s Special:Investigate interface is vulnerable to reflected XSS due to improper escaping of certain internationalized system messages rendered on the “IPs and User agents” tab.
This issue affects Mediawiki - CheckUser extension: from 1.39.X before 1.39.13, from 1.42.X before 1.42.7, from 1.43.X before 1.43.2.
- Record
GHSA-r979-wmj9-cr9m- CVSS 3.1
- 5.4 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
NVD
The CheckUser extension’s Special:Investigate interface is vulnerable to reflected XSS due to improper escaping of certain internationalized system messages rendered on the “IPs and User agents” tab.
This issue affects Mediawiki - CheckUser extension: from 1.39.X before 1.39.13, from 1.42.X before 1.42.7, from 1.43.X before 1.43.2.
- Record
CVE-2025-53478- CVSS 3.1
- 5.4 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2025-53478 is a medium vulnerability (CVSS 5.4) in The Wikimedia Foundation Mediawiki - Checkuser Extension, published July 7, 2025. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.20%, the 10th percentile. No source names a fixed version.