Quick answers
- Is CVE-2026-100243 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-100243 being exploited in the wild.
- How severe is CVE-2026-100243?
- Informational severity, published 29 September 2026.
- Which products and versions are affected?
- Wikimedia Foundation MediaWiki WikiSEO Extension before 1.46.1, 1.45.5, 1.43.10.
- Is there a fix for CVE-2026-100243?
- No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
- How is CVE-2026-100243 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-100243?
- Check whether you run Wikimedia Foundation MediaWiki WikiSEO Extension at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
A stored XSS vulnerability exists in MediaWiki WikiSEO Extension prior to versions 1.46.1, 1.45.5, and 1.43.10 due to improper input neutralization during web page generation. The flaw allows an attacker to inject JavaScript code that persists in the database and is executed in the browsers of subsequent page visitors. An authenticated or unauthenticated user can exploit this via maliciously crafted SEO metadata parameters.
Affected products
- Wikimedia Foundation MediaWiki WikiSEO Extension before 1.46.1, 1.45.5, 1.43.10
Timeline
- 2026-09-29: disclosed