The vulnerability involves HMAC confirmation tokens in Zscaler MCP Server versions 0.7.0 and 0.7.1. Tokens are not bound to the specific resource identifier they protect, a weakness classified as CWE-305. As a result, a client or agent can capture or generate a valid token for one resource and replay it against another resource of the same type, effectively performing the same authorized action on that second resource.

Zscaler MCP Server, vulnerable releases 0.7.0 and 0.7.1, are affected. The issue is resolved in version 0.7.2.

The CVSS Base Score of 4.6 indicates moderate severity. The EPSS score is not available and the vulnerability is not in the CISA KEV catalog. The attack requires an attacker to obtain a legitimate HMAC confirmation token, which can occur if the MCP client or agent is compromised or if an authenticated user can capture the token. Once a token is replayed, the attacker can perform any action that the original token permits on the target resource, potentially allowing unauthorized modification or deletion of resources of the same type.