SSRF Vulnerability in python-utcp via HttpCommunicationProtocol

The python-utcp library, specifically versions prior to 1.1.4, is affected by a server-side request forgery (SSRF) vulnerability identified as CVE-2026-101060. The issue resides in the HttpCommunicationProtocol.call_tool method, which fails to re-validate the target URL when an HTTP redirect is encountered. An attacker who controls a tool endpoint can respond with a 302 redirect to an arbitrary URL. Because the library does not verify the destination post-redirect, the UTCP client will follow the redirect to internal resources, such as cloud metadata services (e.g., 169.254.169.254) or internal HTTP endpoints. The final response body is then returned to the attacker, potentially leading to unauthorized data exfiltration or sensitive configuration disclosure.

Impact

Successful exploitation allows unauthenticated attackers to perform SSRF attacks, enabling access to internal network resources and cloud metadata services. This can result in the exfiltration of sensitive information, such as IAM credentials or internal configuration data, depending on the environment where the application is deployed.

Recommendation

1. Upgrade the python-utcp library to version 1.1.4 or later immediately.
2. Implement outbound network egress filtering on all servers running python-utcp to prevent connections to sensitive ranges like 169.254.169.254.
3. Audit applications using the HttpCommunicationProtocol.call_tool method to identify if they handle untrusted user-supplied URLs.