Ultralytics FastSAM contains a code‑execution flaw in the AutoBackend Model Loading component, specifically in the session.get_modelmeta.custom_metadata_map function. By manipulating the imgsz, names, or kpt_shape arguments the victim can influence the dynamic evaluation used by the library, causing unescaped code directives to be executed. The attack requires local access to the system running FastSAM and can allow an attacker to run arbitrary commands or modify system state on that host.

The affected product is Ultralytics FastSAM, with vulnerability present up to the code commit b4ed20c2fed75eadc5aa7d8b09fedd137b873b52. The project follows a rolling model so no specific version numbers are explicitly listed as fixed or affected. Any deployment of FastSAM before the fix is released may be vulnerable.

The CVSS score of 4.8 indicates a moderate severity. The EPSS score < 1% indicates a very low exploitation probability, and the vulnerability is not listed in the CISA KEV catalog. Because the exploit requires local access and depends on user‑controlled input to the custom_metadata_map, the risk is confined to locally trusted or compromised hosts. In the absence of a patch, successful exploitation would allow an attacker with local privileges to execute arbitrary code on the affected machine.