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

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-16889
StatePUBLISHED
AssignerMON-CSIRT
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-10-29 02:16:51 UTC
Updated2026-10-29 02:16:51 UTC
DescriptionIn 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.

Risk And Classification

Primary CVSS: v4.0 4.8 MEDIUM from 9c1820ae-fb77-4810-a8aa-ca46e7474d2f

CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Problem Types: CWE-434 | CWE-434 CWE-434 Unrestricted upload of file with dangerous type

VersionSourceTypeScoreSeverityVector
4.09c1820ae-fb77-4810-a8aa-ca46e7474d2fSecondary4.8MEDIUMCVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:X/C...
4.0CNACVSS4.8MEDIUMCVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N

CVSS v4.0 Breakdown

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
None
Privileges Required
High
User Interaction
Passive
Confidentiality
None
Integrity
None
Availability
None
Sub Conf.
Low
Sub Integrity
Low
Sub Availability
None

CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Apereo Foundation OpenEQUELLA affected 2019.1 2026.1 custom Not specified

References

ReferenceSourceLinkTags
openequella.github.io/guides 9c1820ae-fb77-4810-a8aa-ca46e7474d2f openequella.github.io
github.com/openequella/openEQUELLA/security/advisories/GHSA-q2xv-rffq-mj5w 9c1820ae-fb77-4810-a8aa-ca46e7474d2f github.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

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

Additional Advisory Data

Solutions

CNA: Update to vendor recommended versions

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