Collabora Online - Built-in CODE Server (richdocumentscode) provides a built-in server with all of the document editing features of Collabora Online. In versions prior to 25.04.702, Collabora Online has a Configuration-Dependent RCE (OS Command Injection) in richdocumentscode proxy. Users of Nextcloud with Collabora Online - Built-in CODE Server app can be vulnerable to attack via proxy.php and an intermediate reverse proxy. This vulnerability is fixed in 25.04.702.
Conclusion & alert: CVE-2025-66208 is rated Moderate Risk (47.2/100): CVSS High severity, with medium exploitation likelihood (EPSS 0.30%). Mandatory action: Review affected assets and schedule remediation.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2026-05-01 | 0.57% | 0.30% | -0.27% |
| 2 | 2026-04-04 | 0.49% | 0.57% | +0.08% |
| 3 | 2025-12-09 | — | 0.49% | — |
Full EPSS history (4 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 7.2 | 4.0 | HIGH |
|
— | — | [email protected] |
| 9.8 | 3.1 | CRITICAL |
|
3.9 | 5.9 | [email protected] |
| URL | Tags |
|---|---|
| https://github.com/CollaboraOnline/online/security/advisories/GHSA-j3q6-q5pc-v5wf | Patch Vendor Advisory |