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MediumVulnerability

GHSA-39j6-4867-gg4w: utcp-http vulnerable to SSRF via attacker-controlled OpenAPI servers[0].url in HTTP communication protocol

Source
GitHub Advisory(opens in a new tab)
Identifiers
CVE-2026-44661GHSA-39j6-4867-gg4w
Published
Record updated
View JSON
Affected
  • utcp-http <= 1.1.1
Fixed in
1.1.2
  • released May 3, 2026, 4 days before disclosure
Known exploitation
Not listed in the CISA Known Exploited Vulnerabilities catalog at the last check.
EPSS
0.2%

Summary

The utcp-http plugin, version 1.1.1 and earlier, contains a blind SSRF flaw. register_manual() checks discovery URLs against an HTTPS or loopback allowlist, but call_tool() and call_tool_streaming() use the resolved tool_call_template.url without revalidating it, so an attacker-hosted OpenAPI spec can declare internal addresses such as http://169.254.169.254 in servers[0].url. A prefix check also let http://localhost.evil.com bypass the loopback rule. The flaw affects the utcp_http.http, utcp_http.streamable_http and utcp_http.sse protocols and can expose cloud metadata and internal services to the LLM caller.

Mitigation

Fixed in 1.1.2 (commit 5b16e43 on dev). The patch adds a utcp_http._security.ensure_secure_url() helper that validates hostnames by parsing, not string prefix, and calls it in register_manual() and before each aiohttp request in call_tool() and call_tool_streaming(). Workarounds: do not call register_manual() with URLs from untrusted parties, even over HTTPS, and restrict the agent host's outbound access to RFC1918, 169.254.0.0/16 and loopback addresses.

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