Quick answers
- Is CVE-2026-103438 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-103438 being exploited in the wild.
- How severe is CVE-2026-103438?
- Informational severity, published 30 September 2026.
- Which products and versions are affected?
- Wikimedia Foundation MediaWiki Wikistories 1.43, 1.45, 1.46.
- Is there a fix for CVE-2026-103438?
- 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-2026-103438 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-103438?
- Check whether you run Wikimedia Foundation MediaWiki Wikistories 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
The vulnerability is a basic reflected or stored XSS flaw in the Wikistories extension where script-related HTML tags are not properly sanitized before output. An attacker can inject arbitrary JavaScript through unfiltered input, which then executes in the context of other users' browsers. The vulnerability affects versions 1.43, 1.45, and 1.46 of the extension.
Affected products
- Wikimedia Foundation MediaWiki Wikistories 1.43, 1.45, 1.46
Timeline
- 2026-09-30: disclosed