Vulnerability identifier: #VU56980

Vulnerability risk: Medium

CVSSv3.1: 4.9 [CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N/E:P/RL:O/RC:C]

CVE-ID: CVE-2021-41798

CWE-ID: CWE-79

Exploitation vector: Network

Exploit availability: Yes

Vulnerable software:
MediaWiki
Web applications / CMS

Vendor: MediaWiki.org

Description

The disclosed vulnerability allows a remote user to perform cross-site scripting (XSS) attacks.

The vulnerability exists due to insufficient sanitization of user-supplied data in Special:Search. A remote user can permanently inject and execute arbitrary HTML and script code in user's browser in context of vulnerable website.

Successful exploitation of this vulnerability may allow a remote attacker to steal potentially sensitive information, change appearance of the web page, perform phishing and drive-by-download attacks.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

MediaWiki: 1.31.0 - 1.31.15, 1.35 - 1.35.3, 1.36.0 - 1.36.1, 1.34 - 1.34.4, 1.33.0 - 1.33.4, 1.32.0 - 1.32.6, 1.30.0 - 1.30.2

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External links
http://lists.wikimedia.org/hyperkitty/list/mediawiki-announce@lists.wikimedia.org/thread/2IFS5CM2YV4VMSODPX3J2LFHKSEWVFV5/
http://phabricator.wikimedia.org/T285515

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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. However, proof of concept for this vulnerability is available.