#VU52560 Exposure of Resource to Wrong Sphere in MediaWiki - CVE-2021-31547

Vulnerability identifier: #VU52560

Vulnerability risk: Low

CVSSv4.0: 1.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2021-31547

CWE-ID: N/A

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
MediaWiki
Web applications / CMS

Vendor: MediaWiki.org

Description

The vulnerability allows a remote attacker to compromise the target system.

The vulnerability exists due to exposure of resource to wrong sphere issue in the AbuseFilter extension. A remote authenticated attacker can reveal suppressed edits and usernames through the iteration of crafted AbuseFilter rules.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

MediaWiki: 1.31.0 - 1.35.1

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External links
https://lists.wikimedia.org/pipermail/mediawiki-announce/2021-April/000274.html
https://gerrit.wikimedia.org/r/q/I4900b1be73323599d74e3164447f81eded094d75
https://phabricator.wikimedia.org/T223654
https://gerrit.wikimedia.org/r/q/I3f7dbd8b873d411e37c8c3aac2339bf5ec36907d

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.