Quick answers
- Is CVE-2026-16889 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-16889 being exploited in the wild.
- How severe is CVE-2026-16889?
- Informational severity, published 29 October 2026.
- Which products and versions are affected?
- openEQUELLA before 2026.1.
- Is there a fix for CVE-2026-16889?
- Yes: fixed in 2026.1. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-16889 attacked?
- It is attacked over the network, in a web application.
- Am I affected by CVE-2026-16889?
- Check whether you run openEQUELLA 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.
How to fix
- Fixed in: 2026.1
Technical details
The PUT /api/preloginnotice/image/{name} endpoint fails to validate uploaded file types and derives the Content-Type header from the supplied filename. An authenticated user with EDIT_SYSTEM_SETTINGS permission can upload an HTML file containing JavaScript, which is stored and served with Content-Type: text/html from the openEQUELLA origin, resulting in stored cross-site scripting. Unauthenticated exploitation is possible if EDIT_SYSTEM_SETTINGS has been granted to guest or all-users groups.
Affected products
- openEQUELLA openEQUELLA before 2026.1