CVE-2026-45369: python-utcp OS command injection in CLI communication protocol

CVE-2026-45369 · Severity: critical · CVSS 10 · Published 2026-05-14

python-utcp is a library used to implement the Universal Tool Calling Protocol, which allows software to interact with various command-line tools. A security flaw in how the library handles user-provided arguments allows an attacker to execute unauthorized commands on the underlying operating system. This could lead to a complete system takeover, data theft, or service disruption if the library processes untrusted input.

Technologies: Universal Tool Calling Protocol Python-Utcp. Vendors: PyPI, Universal Tool Calling Protocol.

Quick answers

Is CVE-2026-45369 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-45369 being exploited in the wild.
How severe is CVE-2026-45369?
Critical severity, with a CVSS score of 10, published 14 May 2026.
Which products and versions are affected?
utcp-cli (PyPI) <= 1.1.1, ECOSYSTEM:introduced=0,fixed=1.1.2; Universal Tool Calling Protocol Python-Utcp < 1.1.2.
Is there a fix for CVE-2026-45369?
Yes. utcp-cli (PyPI): upgrade to 1.1.2 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-45369 attacked?
It is attacked over the network, in a software library.
Am I affected by CVE-2026-45369?
Check whether you run utcp-cli (PyPI) or Universal Tool Calling Protocol Python-Utcp at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • utcp-cli (PyPI): upgrade to 1.1.2 or later
    pip install "utcp-cli>=1.1.2"

Technical details

An OS command injection vulnerability exists in the `_substitute_utcp_args` method within `cli_communication_protocol.py` of the python-utcp library. The component fails to sanitize or escape user-controlled `tool_args` before inserting them into shell command strings, which are subsequently executed via `/bin/bash -c` on Unix or `powershell.exe -Command` on Windows. An attacker can exploit this by supplying arguments containing shell metacharacters (e.g., semicolons, pipes, or backticks) to achieve arbitrary code execution. The vulnerability is triggered when the library processes a tool call with malicious arguments, typically requiring some level of user interaction or a specific application flow. This issue is resolved in version 1.1.2 by implementing proper shell-quoting using `shlex.quote` and PowerShell-specific escaping.

Affected products

  • universal-tool-calling-protocol python-utcp (utcp-cli) < 1.1.2

Identifiers

  • CVE-2026-45369
  • GHSA-33p6-5jxp-p3x4
  • PYSEC-2026-560

Timeline

  • 2026-05-10: advisory: GitHub Security Advisory published
  • 2026-05-14: disclosed: CVE-2026-45369 published to NVD

References

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