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

> Attackers can force the library to make requests to internal services by hosting malicious OpenAPI specs, bypassing URL validation checks.

- **Severity:** Medium 4.7 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 14 May 2026
- **Updated:** 15 May 2026
- **Also known as:** GHSA-39j6-4867-gg4w, PYSEC-2026-3396

## What is CVE-2026-44661?

CVE-2026-44661 is a medium-severity server-side request forgery vulnerability in universal-tool-calling-protocol python-utcp, published on 14 May 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

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.

Weakness: CWE-918 (Server-Side Request Forgery)

## Which versions are affected by CVE-2026-44661?

3 open source packages ship an affected version, including utcp-http.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `utcp-http` | PyPI | All versions | 1.1.2 |
| `utcp-http` | PyPI | All versions | 1.1.2 |
| `utcp-http` | PyPI | All versions | 1.1.2 |

## How do I fix CVE-2026-44661?

Upgrade utcp-http to 1.1.2 or later.

## Is CVE-2026-44661 being exploited?

There is no known exploitation of CVE-2026-44661 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-44661 and fix it if it is affected.

What it is: CVE-2026-44661 is a medium-severity server-side request forgery vulnerability in universal-tool-calling-protocol python-utcp, published on 14 May 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-44661 in the wild and no public exploit code.

Affected packages and fixed versions:
- utcp-http (PyPI): affected all versions; fixed in 1.1.2
- utcp-http (PyPI): affected all versions; fixed in 1.1.2
- utcp-http (PyPI): affected all versions; fixed in 1.1.2

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-44661/ (Markdown: https://insights.sbomify.com/CVE-2026-44661/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-44661
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-44661
- OSV: https://osv.dev/vulnerability/CVE-2026-44661

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-44661/
Summaries are generated and may contain mistakes; the official description above is the record.