CVE-2026-39935 XSS-via-i18n in localised wiki names
Cross-site scripting vulnerability in MediaWiki CampaignEvents Extension allows attackers to inject malicious scripts via localized wiki names.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-39935?
CVE-2026-39935 is a medium-severity cross-site scripting vulnerability in The Wikimedia Foundation Mediawiki - CampaignEvents Extension, published on 7 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Improper neutralization of input during web page generation ('cross-site scripting') vulnerability in The Wikimedia Foundation Mediawiki - CampaignEvents Extension allows Cross-Site Scripting (XSS). This issue was remediated only on the `master` branch.
Weakness: CWE-79
Which versions are affected by CVE-2026-39935?
How do I fix CVE-2026-39935?
No fix has been published for CVE-2026-39935 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-2026-39935 being exploited?
There is no known exploitation of CVE-2026-39935 in the wild and no public exploit code.
Sources
Also known as GHSA-g2mp-vfg6-8xwm.