CVE-2026-55552: Yamcs unauthenticated directory traversal

Executive brief

Yamcs is an open-source mission control system used to manage and monitor satellite operations and other space-related infrastructure. This vulnerability allows anyone on the network to download any file from the server's operating system—including configuration files, credentials, and system files—without needing to log in. An attacker could retrieve sensitive data that could lead to further compromise of the system or exposure of operational secrets.

Technical details

This is a path traversal (CWE-22) vulnerability affecting the static file serving functionality in HttpRequestHandler.java and StaticFileHandler.java. The vulnerability allows unauthenticated attackers to bypass directory restrictions by injecting path traversal sequences (e.g., `//etc/passwd`) into HTTP requests. No authentication or user interaction is required; the flaw is exploitable directly over the network via HTTP. An attacker can download any file readable by the Yamcs process user, including system configuration, application secrets, and potentially private keys. The vulnerability was patched in versions 5.11.13 and 5.12.0.

Affected products

• Yamcs Yamcs <5.11.13

Timeline

• 2026-07-14: disclosed: Initial disclosure to GitHub Advisory Database
• 2026-08-28: advisory: Published to GitHub Advisory Database

References

• https://api.github.com/users/suffs811
• https://github.com/suffs811
• https://api.github.com/users/suffs811/gists%7B/gist_id%7D
• https://api.github.com/users/suffs811/repos
• https://avatars.githubusercontent.com/u/84633135?v=4
• https://api.github.com/users/suffs811/events%7B/privacy%7D