{"id":"CVE-2026-48164","published":"2026-10-30T15:16:52.217","lastModified":"2026-10-30T19:37:07.073","description":"Collabora Online is a collaborative online office suite based on LibreOffice technology. Prior to 24.04.18 and 25.04.11, the `host_session_id` query/form parameter is substituted into the `cool.html` editor page without HTML encoding, unlike parameters passed through the existing variable-encoding mechanism. An attacker who induces a victim to load a crafted URL can inject HTML and, in the absence of an effective `Content Security Policy`, execute scripts in the Collabora Online iframe's origin, exposing the session authentication token and page contents. A reverse proxy that preserves the `Content Security Policy` header sent by `coolwsd` mitigates the script-execution scenario. This issue is fixed in versions 24.04.18 and 25.04.11.","cvssScore":4.7,"cvssSeverity":"MEDIUM","cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:L/A:N","cwes":["CWE-79"],"vendors":[],"products":[],"references":[{"url":"https://github.com/CollaboraOnline/online/commit/2d4469d27f0c52f4b28b64090e60452d2e147279","tags":[]},{"url":"https://github.com/CollaboraOnline/online/security/advisories/GHSA-wgmm-q3ch-64jj","tags":[]}],"exploitRefs":[{"url":"https://github.com/CollaboraOnline/online/commit/2d4469d27f0c52f4b28b64090e60452d2e147279","tags":[]},{"url":"https://github.com/CollaboraOnline/online/security/advisories/GHSA-wgmm-q3ch-64jj","tags":[]}],"hasPoc":true,"ai":null}