CVE-2026-48164: medium-severity vulnerability in CollaboraOnline online
Collabora Online: Reflected HTML injection through host_session_id
Published
E-mail alert when it lands in KEV, gets a public PoC or its score goes up.
13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 4.7epss 0.3%
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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:L/A:N
Affected products
CollaboraOnline · onlineRelated CVEs — CollaboraOnline online
In the same product, most dangerous first.
CVE-2025-66208HIGHConfiguration-Dependent RCE (OS Command Injection) in richdocumentscode proxyEPSS 1.8%CVE-2021-32744CRITICALUnauthenticated attacker could gain access to currently open filesEPSS 1.1%CVE-2021-43817HIGHReflected Cross-Site-Scripting vulnerability in Collabora OnlineEPSS 0.7%CVE-2021-32745HIGHReflected Cross-Site-Scripting vulnerabilityEPSS 0.6%CVE-2025-24796MEDIUMRemote Code Execution within Collabora Online jail with Macros EnabledEPSS 0.5%CVE-2023-49788HIGHImproper handling of browser-side provided input in richdocuments path handlingEPSS 0.5%