CVE-2026-101058
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:P/VC:H/VI:L/VA:N/SC:H/SI:L/SA:N
Summary
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.
Affected Software
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| universal-tool-calling-protocol | python-utcp | 0 < 1.1.12 | affected |
| universal-tool-calling-protocol | python-utcp | 1.1.12 | unaffected |
Weaknesses
- CWE-918: Server-Side Request Forgery (SSRF)
References
- https://github.com/universal-tool-calling-protocol/python-utcp/security/advisories/GHSA-8vxx-v7r9-948g
- https://www.vulncheck.com/advisories/python-utcp-before-1.1.12-ssrf-via-remote-http-manual
Feedback
Was this page helpful?
Glad to hear it! Please tell us how we can improve.
Sorry to hear that. Please tell us how we can improve.