CVE-2026-44661 json
python-utcp: SSRF via attacker-controlled OpenAPI servers[0].url in HTTP communication protocol
published 2026-05-07 6 mo ago modified 2026-10-26 14 d ago also GHSA-39j6-4867-gg4w , PYSEC-2026-3396 , EUVD-2026-30479
- cvss
- 4.7
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.2%
- EPSS 0.2% chance of exploitation in 30 days, percentile 7%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- pypi utcp-http 1.1.2
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 5 mo ago
Exploit prediction
0.18% chance of exploitation in the next 30 days, higher than 7% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 4.7 | CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N |
| GitHub | 3.1 | 4.7 | CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N |
| OSV | 3.1 | 4.7 | CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| pypi | utcp-http | <1.1.2 |
1.1.2 |
Affected products
- universal-tool-calling-protocol python-utcp
Classification
- Weakness
-
- CWE-918 Server-Side Request Forgery
References
-
github.com
/universal-tool-calling-protocol/python-utcp/security/advisories/GHSA-39j6-4867-gg4w
web
-
nvd.nist.gov
/vuln/detail/CVE-2026-44661
advisory
-
github.com
/universal-tool-calling-protocol/python-utcp
package
-
pypi.org
/project/utcp-http
package
-
github.com
/advisories/GHSA-39j6-4867-gg4w
advisory
Sources
- CVE List CVE-2026-44661
- GitHub Advisory GHSA-39j6-4867-gg4w
- NVD CVE-2026-44661
- OSV PYSEC-2026-3396
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.