CVE-2026-103439 Various rawParams() and escaped() updates to prevent XSS in Wikibase extension
Cross-site scripting vulnerability in the MediaWiki Wikibase extension allows attackers to inject malicious scripts into web pages viewed by other users.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-103439?
CVE-2026-103439 is a low-severity cross-site scripting vulnerability in The Wikimedia Foundation MediaWiki Wikbase extension, published on 30 Sep 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official description
Improper neutralization of Script-Related HTML tags in a web page (basic XSS) vulnerability in The Wikimedia Foundation MediaWiki Wikbase extension allows Cross-Site Scripting (XSS).
This issue affects MediaWiki Wikbase extension: 1.46, 1.45, and 1.43.
Weakness: CWE-80
Which versions are affected by CVE-2026-103439?
How do I fix CVE-2026-103439?
No fix has been published for CVE-2026-103439 yet. Limit exposure of the affected software until one is available.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-103439 being exploited?
There is no known exploitation of CVE-2026-103439 in the wild and no public exploit code.
Sources
Also known as GHSA-mfg6-8655-c3r3.