CVE-2026-103443 API permits session-seeded javascript URL XSS
An attacker can inject malicious JavaScript via session-seeded URLs in the MediaWiki Book extension, potentially compromising user sessions.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-103443?
CVE-2026-103443 is a low-severity cross-site scripting vulnerability in The Wikimedia Foundation MediaWiki Collection (Book) extension, published on 30 Sep 2026. Any signed-in user can exploit it over the 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 Collection (Book) extension allows XSS Targeting Non-Script Elements.
This issue affects MediaWiki Collection (Book) extension: 1.46, 1.45, and 1.43.
Weakness: CWE-80
Which versions are affected by CVE-2026-103443?
How do I fix CVE-2026-103443?
No fix has been published for CVE-2026-103443 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-2026-103443 being exploited?
There is no known exploitation of CVE-2026-103443 in the wild and no public exploit code.
Sources
Also known as GHSA-2fmc-4qg7-7m8x.