utcp-http SSRF: HTTP tool invocation follows redirects without re-validating the target

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

8.2 · CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

Summary HttpCommunicationProtocol.calltool validates only the pre-redirect tool URL, then issues the request with redirects enabled and never re-checks where it lands. A tool whose endpoint is an attacker-controlled public URL can therefore 302-redirect the UTCP client into an internal service including the cloud metadata endpoint and the response body is returned to the tool caller. This is a working SSRF + internal-data-exfiltration primitive. This is the redirect invariant of the SSRF class fixed in GHSA-39j6-4867-gg4w; that fix added an invocation-time URL check but left the redirect hop unguarded. This vector bypasses the GHSA-39j6-4867-gg4w mitigation via unvalidated redirects. Root cause 1. The resolved URL is validated once, before the request: https://github.com/universal-tool-calling-protocol/python-utcp/blob/4ed0a48b84a452338bd3e996efb0d169e8d75ac2/plugins/communicationprotocols/http/src/utcphttp/httpcommunicationprotocol.py#L281 2. The request is then made with aiohttp's…

Published by the source

25 Aug 2026, 15:48 UTC

Last modified by the source

25 Aug 2026, 15:48 UTC

Source last checked

26 Oct 2026, 13:50 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-9qhg-99ww-9mqc

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# Patch Next advisory brief: GHSA-9qhg-99ww-9mqc

Advisory: utcp-http SSRF: HTTP tool invocation follows redirects without re-validating the target
IDs: GHSA-9qhg-99ww-9mqc
Record: https://patchnext.com/advisories/ghsa-9qhg-99ww-9mqc (revision 1, source checked 26 Oct 2026, 13:50 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.2)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: utcp-http 1.1.4. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI utcp-http: affected <= 1.1.3; fixed in 1.1.4

## Suggested inspection (read-only)
- `python -m pip show utcp-http`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on utcp-http.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-9qhg-99ww-9mqc (GitHub-reviewed advisory GHSA-9qhg-99ww-9mqc lists affected ranges: PyPI utcp-http >=0 <=1.1.3)

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