universal-tool-calling-protocol utcp-http up to 1.1.11 Manual URL Verification server-side request forgery

Summaryinfo

A vulnerability has been found in universal-tool-calling-protocol utcp-http up to 1.1.11 and classified as critical. This issue affects some unknown processing of the component Manual URL Verification. Performing a manipulation results in server-side request forgery. This vulnerability is identified as CVE-2026-101058. The attack can be initiated remotely. There is not any exploit available. The affected component should be upgraded.

Detailsinfo

A vulnerability classified as critical has been found in universal-tool-calling-protocol utcp-http up to 1.1.11. This affects an unknown part of the component Manual URL Verification. The manipulation with an unknown input leads to a server-side request forgery vulnerability. CWE is classifying the issue as CWE-918. The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

python-utcp (pip package utcp-http) before 1.1.12 does not verify whether tool URLs declared in a hand-written UTCP manual point at the agent's own loopback interface when that manual is discovered from a remote, non-loopback origin. Because ensure_secure_url intentionally permits loopback HTTP for local development and native manuals bypassed the loopback check performed by the OpenAPI converter, an attacker who can serve a UTCP manual that a victim registers can cause the client to issue requests to services bound only to 127.0.0.1 on the victim host and have the response bodies returned to the caller (server-side request forgery). The http, sse and streamable_http protocols are all affected. Reach is limited to loopback, and exploitation further requires a loopback service that answers unauthenticated requests with useful data. Fixed in utcp-http 1.1.12, which rejects manuals fetched from a non-loopback origin that declare loopback tool URLs, keyed off the final post-redirect discovery URL.

It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2026-101058 since 09/27/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. It demands that the victim is doing some kind of user interaction. The technical details are unknown and an exploit is not publicly available.

Upgrading to version 1.1.12 eliminates this vulnerability.

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Productinfo

Vendor

• universal-tool-calling-protocol

Name

• utcp-http

Version

• 1.1.0
• 1.1.1
• 1.1.2
• 1.1.3
• 1.1.4
• 1.1.5
• 1.1.6
• 1.1.7
• 1.1.8
• 1.1.9
• 1.1.10
• 1.1.11

CPE 2.3info

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CPE 2.2info

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