{"id":"CVE-2026-16889","state":"PUBLISHED","title":"Stored XSS via Pre-Login Notice Image Upload Serves Attacker HTML from Application Origin","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.","publishedAt":"2026-10-29T01:32:09.466Z","updatedAt":"2026-10-29T02:02:13.700Z","severity":{"score":4.8,"label":"Medium","version":"4.0","vector":"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","source":"MON-CSIRT"},"assigner":"MON-CSIRT","products":["Apereo Foundation openEQUELLA"],"affected":[{"vendor":"Apereo Foundation","product":"openEQUELLA","defaultStatus":"unaffected","versions":[{"version":"2019.1","status":"affected","lessThan":"2026.1","versionType":"custom"}]}],"references":["https://github.com/openequella/openEQUELLA/security/advisories/GHSA-q2xv-rffq-mj5w","https://openequella.github.io/guides/"],"weaknesses":["CWE-434"],"ingestedAt":"2026-10-29T20:11:00.674Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/16xxx/CVE-2026-16889.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-16889","state":"PUBLISHED","datePublished":"2026-10-29T01:32:09.466Z","dateUpdated":"2026-10-29T02:02:13.700Z","assignerShortName":"MON-CSIRT","assignerOrgId":"9c1820ae-fb77-4810-a8aa-ca46e7474d2f","dateReserved":"2026-07-24T05:06:16.448Z"},"containers":{"cna":{"title":"Stored XSS via Pre-Login Notice Image Upload Serves Attacker HTML from Application Origin","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"Apereo Foundation","product":"openEQUELLA","defaultStatus":"unaffected","versions":[{"version":"2019.1","status":"affected","lessThan":"2026.1","versionType":"custom"}]}],"references":[{"url":"https://github.com/openequella/openEQUELLA/security/advisories/GHSA-q2xv-rffq-mj5w","tags":["vendor-advisory"]},{"url":"https://openequella.github.io/guides/","tags":["product"]}],"metrics":[{"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}],"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"HIGH","userInteraction":"PASSIVE","vulnConfidentialityImpact":"NONE","subConfidentialityImpact":"LOW","vulnIntegrityImpact":"NONE","subIntegrityImpact":"LOW","vulnAvailabilityImpact":"NONE","subAvailabilityImpact":"NONE","exploitMaturity":"NOT_DEFINED","Safety":"NOT_DEFINED","Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","valueDensity":"NOT_DEFINED","vulnerabilityResponseEffort":"NOT_DEFINED","providerUrgency":"NOT_DEFINED","version":"4.0","baseSeverity":"MEDIUM","baseScore":4.8,"vectorString":"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"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-434","lang":"en","description":"CWE-434 Unrestricted upload of file with dangerous type","type":"CWE"}]}],"providerMetadata":{"shortName":"MON-CSIRT","orgId":"9c1820ae-fb77-4810-a8aa-ca46e7474d2f","dateUpdated":"2026-10-29T01:32:09.466Z"},"impacts":[{"capecId":"CAPEC-592","descriptions":[{"lang":"en","value":"CAPEC-592 Stored XSS"}]},{"capecId":"CAPEC-23","descriptions":[{"lang":"en","value":"CAPEC-23 File Content Injection"}]}],"solutions":[{"lang":"en","value":"Update to vendor recommended versions","supportingMedia":[{"type":"text/html","base64":false,"value":"<p>Update to vendor recommended versions</p><br>"}]}],"credits":[{"lang":"en","value":"Lê Ngọc Bảo Minh ( University of Information Technology: VNUHCM - UIT )","type":"finder"}],"source":{"discovery":"UNKNOWN"},"x_generator":{"engine":"Vulnogram 1.0.4"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-16889","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"version":"2.0.3","timestamp":"2026-10-29T01:51:03.808908Z"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-29T02:02:13.700Z"}}]}}}