How severe is CVE-2025-66208?

CVE-2025-66208 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2025-66208 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (58th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-66208?

CVE-2025-66208 affects Collabora Online. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2025-66208?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

Does CVE-2025-66208 have an EU (EUVD) identifier?

Yes. CVE-2025-66208 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-201097.

When was CVE-2025-66208 published?

CVE-2025-66208 was published on 2025-12-03 and last updated on 2026-06-17.

CVE-2025-66208

CVE-2025-66208 is a critical-severity vulnerability in Collabora Online with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-78.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v4: 7.2
EPSS exploit prediction: 1% (58th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-201097
Weakness: CWE-78
Affected product: Collabora Online
Published: 2025-12-03
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2025-66208?: 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.
How severe is CVE-2025-66208?: CVE-2025-66208 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2025-66208 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (58th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-66208?: CVE-2025-66208 affects Collabora Online. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-66208?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2025-66208 have an EU (EUVD) identifier?: Yes. CVE-2025-66208 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-201097.
When was CVE-2025-66208 published?: CVE-2025-66208 was published on 2025-12-03 and last updated on 2026-06-17.

References

https://github.com/CollaboraOnline/online/security/advisories/GHSA-j3q6-q5pc-v5wf

Affected products (1)

cpe:2.3:a:collabora:online:*:*:*:*:*:*:*:*

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