The vulnerability is a bucket squatting flaw that allows an attacker to take over the Cloud Run MCP service account. By impersonating the bucket name, the attacker can intercept traffic, read proprietary source code, launch arbitrary code execution, and exfiltrate confidential data. The flaw is rooted in improper origin verification, classified as CWE-340.

Affected systems are Google Cloud Platform customers deployed with Cloud Run MCP versions prior to 1.11.0. The issue exists in all releases of the Cloud Run Microservices Controller that do not implement bucket name validation, so any public or private bucket with an identical name can be used to subvert the service.

The CVSS score of 7.7 indicates a high severity risk. No EPSS data is available, and it is not listed in CISA's KEV catalog, which suggests that the exploitation probability may be lower but still significant for exposed environments. The likely attack vector involves an attacker creating a bucket with a matching name in the same project or region, thereby hijacking traffic directed to the vulnerable service. If exploited, an attacker gains full control over the service account and can execute arbitrary commands or exfiltrate data.