CollaboraOnline up to 25.04.701 Built-in CODE Server App proxy.php os command injection

Summaryinfo

A vulnerability marked as critical has been reported in CollaboraOnline Online up to 25.04.701. Affected by this vulnerability is an unknown functionality of the file proxy.php of the component Built-in CODE Server App. Performing a manipulation results in os command injection. This vulnerability is identified as CVE-2025-66208. The attack can be initiated remotely. There is not any exploit available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as very critical, was found in CollaboraOnline Online up to 25.04.701. This affects an unknown code of the file proxy.php of the component Built-in CODE Server App. The manipulation with an unknown input leads to a os command injection vulnerability. CWE is classifying the issue as CWE-78. The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

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.

It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2025-66208 since 11/25/2025. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 12/08/2025). The attack technique deployed by this issue is T1202 according to MITRE ATT&CK.

By approaching the search of inurl:proxy.php it is possible to find vulnerable targets with Google Hacking.

Upgrading to version 25.04.702 eliminates this vulnerability.

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Productinfo

Vendor

• CollaboraOnline

Name

• Online

Version

• 25.04.701

Website

• Product: https://github.com/CollaboraOnline/online/

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