{"id":"CVE-2026-16889","aliases":["EUVD-2026-112563","GHSA-jj9r-xgj6-prvj","GHSA-q2xv-rffq-mj5w"],"status":"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.","severity":{"version":"4.0","score":4.8,"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","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-09","score":0.00315,"percentile":0.24578,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-434"],"published":"2026-10-29T01:32:09Z","modified":"2026-10-31T02:30:27Z","products":[{"vendor":"apereo foundation","product":"openequella"},{"vendor":"openequella","product":"openequella"}],"references":[{"url":"https://github.com/openequella/openEQUELLA/security/advisories/GHSA-q2xv-rffq-mj5w","tags":["vendor-advisory","advisory"]},{"url":"https://openequella.github.io/guides/","tags":["product","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-16889"},{"url":"https://openequella.github.io/guides"},{"url":"https://github.com/advisories/GHSA-jj9r-xgj6-prvj"}],"sources":{"cve":[{"id":"CVE-2026-16889","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.","status":"published","published":"2026-10-29T01:32:09.466Z","modified":"2026-10-29T02:02:13.7Z","cvss":[{"version":"4.0","score":4.8,"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","level":"medium","assessor":"cna"}],"cwes":["CWE-434"],"updated_at":"2026-11-02T14:20:10.870108Z"}],"euvd":[{"id":"EUVD-2026-112563","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.","status":"published","published":"2026-10-29T01:32:09Z","modified":"2026-10-29T02:02:13Z","cvss":[{"version":"4.0","score":4.8,"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","level":"medium"}],"updated_at":"2026-11-02T16:59:18.059516Z"}],"ghsa":[{"id":"GHSA-jj9r-xgj6-prvj","title":"In openEQUELLA before 2026.1, the pre-login notice image upload endpoint (PUT /api/preloginnotice...","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.","status":"published","published":"2026-10-29T03:30:29Z","modified":"2026-10-29T03:30:37Z","cvss":[{"version":"4.0","score":4.8,"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/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","level":"medium"}],"cwes":["CWE-434"],"updated_at":"2026-11-02T15:14:37.567324Z"}],"nvd":[{"id":"CVE-2026-16889","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.","status":"published","published":"2026-10-29T02:16:51.803Z","modified":"2026-10-29T15:56:34.127Z","cvss":[{"version":"4.0","score":4.8,"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/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","level":"medium","assessor":"secondary"}],"cwes":["CWE-434"],"updated_at":"2026-11-02T14:13:04.6346Z"}],"osv":[{"id":"CVE-2026-16889","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.","status":"published","published":"2026-10-29T02:16:51.803Z","modified":"2026-10-31T02:30:27.725445529Z","cvss":[{"version":"4.0","score":4.8,"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/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","level":"medium"}],"updated_at":"2026-11-02T15:44:57.682091Z"}]}}