coder code-server up to 4.99.3 URL confused deputy

Summaryinfo

A vulnerability, which was classified as critical, was found in coder code-server up to 4.99.3. Affected by this issue is some unknown functionality of the component URL Handler. Executing a manipulation can lead to confused deputy. The identification of this vulnerability is CVE-2025-47269. The attack may be launched remotely. There is no exploit available. You should upgrade the affected component.

Detailsinfo

A vulnerability has been found in coder code-server up to 4.99.3 and classified as critical. This vulnerability affects some unknown functionality of the component URL Handler. The manipulation with an unknown input leads to a confused deputy vulnerability. The CWE definition for the vulnerability is CWE-441. The product receives a request, message, or directive from an upstream component, but the product does not sufficiently preserve the original source of the request before forwarding the request to an external actor that is outside of the product's control sphere. This causes the product to appear to be the source of the request, leading it to act as a proxy or other intermediary between the upstream component and the external actor. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

code-server runs VS Code on any machine anywhere through browser access. Prior to version 4.99.4, a maliciously crafted URL using the proxy subpath can result in the attacker gaining access to the session token. Failure to properly validate the port for a proxy request can result in proxying to an arbitrary domain. The malicious URL `https:///proxy/[email protected]/path` would be proxied to `[email protected]/path` where the attacker could exfiltrate a user's session token. Any user who runs code-server with the built-in proxy enabled and clicks on maliciously crafted links that go to their code-server instances with reference to /proxy. Normally this is used to proxy local ports, however the URL can reference the attacker's domain instead, and the connection is then proxied to that domain, which will include sending cookies. With access to the session cookie, the attacker can then log into code-server and have full access to the machine hosting code-server as the user running code-server. This issue has been patched in version 4.99.4.

The advisory is available at github.com. This vulnerability was named CVE-2025-47269 since 05/05/2025. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. Successful exploitation requires user interaction by the victim. The technical details are unknown and an exploit is not available.

Upgrading to version 4.99.4 eliminates this vulnerability. The upgrade is hosted for download at github.com. Applying the patch 47d6d3ada5aadef6d221f3d612401eb3dad9299e is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Vendor

• coder

Name

• code-server

Version

• 4.99.0
• 4.99.1
• 4.99.2
• 4.99.3

License

• open-source

Website

• Product: https://github.com/coder/code-server/

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