CVE-2026-16889

UNKNOWN 0.0

Stored XSS via Pre-Login Notice Image Upload Serves Attacker HTML from Application Origin

CVSS Score

0.0

EPSS Score

0.0%

EPSS Percentile

0th

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.

CWE	CWE-434
Vendor	apereo foundation
Product	openequella
Published	Oct 29, 2026
Last Updated	Oct 29, 2026

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Affected Versions

Apereo Foundation / openEQUELLA

2019.1 < 2026.1

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/openequella/openEQUELLA/security/advisories/GHSA-q2xv-rffq-mj5w openequella.github.io: https://openequella.github.io/guides/

Credits

Lê Ngọc Bảo Minh ( University of Information Technology: VNUHCM - UIT )