Dalfox is a tool for detecting cross‑site scripting. In server mode, the application listens on 0.0.0.0:6664 by default without requiring an API key. The request body for /scan is deserialized into model.Options, and the FoundAction and FoundActionShell fields are passed directly into the scan routine. An unauthenticated client can therefore inject a shell command that Dalfox will execute whenever a scan result is found, giving an attacker full remote code execution on the host.

The issue affects Dalfox releases prior to v2.13.0 when run in REST API server mode. Any installation of the dalfox utility from the hahwul project that has not been upgraded and that exposes the default port is vulnerable.

The flaw carries a CVSS score of 10, indicating maximum severity. The EPSS score is not available, and the vulnerability is not listed in the CISA KEV catalog. The attack vector is remote and unauthenticated: any host that can reach the server on port 6664 can send a crafted POST /scan request with a payload containing a FoundAction or FoundActionShell value, resulting in arbitrary code execution. No additional privileges or dependencies are required, making exploitation straightforward for the attacker.