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Medium 4.7Published May 14, 2026

CVE-2026-44661python-utcp: SSRF via attacker-controlled OpenAPI servers[0].url in HTTP communication protocol

Updated under an hour ago ()

Does this affect you?

It affects universal-tool-calling-protocol python-utcp. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

python-utcp is the python implementation of UTCP. Prior to 1.1.3, the utcp-http plugin is vulnerable to a blind Server-Side Request Forgery (SSRF) caused by a trust-boundary inconsistency between manual discovery and tool invocation. register_manual() validates the discovery URL against an HTTPS / loopback allowlist, but call_tool() and call_tool_streaming() reuse the resolved tool_call_template.url directly without revalidating, and the OpenAPI converter blindly trusts whatever servers[0].url an attacker-hosted spec declares. An attacker who hosts a malicious OpenAPI spec on a legitimate HTTPS endpoint can declare e.g. servers: [{ url: "http://127.0.0.1:9090" }] or servers: [{ url: "http://169.254.169.254" }]; the OpenAPI converter then produces tools whose URL points at internal services on the agent host. All three HTTP-class protocols (utcp_http.http, utcp_http.streamable_http, utcp_http.sse) shared the same gap. This vulnerability is fixed in 1.1.3.

CVSS
4.7 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N
Weakness (CWE)
CWE-918
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
Not loaded for this CVE
Assigned by
GitHub_M
NVD analysis
Deferred
Record last updated
May 15, 2026
First seen by InfoSec Signals
Oct 9, 2026

Affected products

Affected products
universal-tool-calling-protocol python-utcp
universal_tool_calling_protocol:python_utcp (from the name)
before 1.1.2
CNA record

References

References

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

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