CVE-2026-16889
Received
Received - Intake
Stored XSS in openEQUELLA Pre-Login Notice Image Upload
Vulnerability report for CVE-2026-16889, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.
Publication date: 2026-10-29
Last updated on: 2026-10-29
Assigner: MON-CSIRT
Description
Description
In openEQUELLA before 2026.1, the pre-login notice image upload endpoint (PUT /api/preloginnotice/image/{name}) does not validate the type of uploaded files and serves them with a Content-Type derived from the supplied filename. A user holding the EDIT_SYSTEM_SETTINGS permission can upload an HTML file that is then served as text/html from the openEQUELLA origin, resulting in stored cross-site scripting. Unauthenticated exploitation is possible where EDIT_SYSTEM_SETTINGS has been granted to the guest user or everyone.
CVSS Scores
EPSS Scores
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| Percentile: |
Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| Apereo Foundation | openEQUELLA | 2019.1 |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-434 | The product allows the upload or transfer of dangerous file types that are automatically processed within its environment. |
