CVE-2026-48164
Dashboard / Vulnerabilities / CVE-2026-48164
Summary: Collabora Online: Reflected HTML injection through host_session_id
Details: 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.
References: https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/48xxx/CVE-2026-48164.json, https://github.com/CollaboraOnline/online/security/advisories/GHSA-wgmm-q3ch-64jj, https://nvd.nist.gov/vuln/detail/CVE-2026-48164, https://github.com/CollaboraOnline/online/commit/2d4469d27f0c52f4b28b64090e60452d2e147279
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