Security Digest · Vulnerability record
CVE-2026-45369: utcp-cli Vulnerable to Command Injection via Unsanitized Argument Substitution in CLI Communication Protocol
python-utcp is the python implementation of UTCP.
CVSS 8.3 High EPSS 0.4% · p28
Should you act?
Normal patch cycle
No exploitation signal; fix it in your next routine update if you are affected. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- Not in CISA KEV, but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 0.4%, percentile 28: FIRST’s model estimates a 0.4% chance of exploitation activity in the next 30 days, higher than 28% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Needs a user to click or open something. Phishing makes that realistic, but it is not wormable.
- Only applies if your dependency tree includes
utcp-cli(PyPI) <= 1.1.1, fixed in 1.1.2. Check your lockfile, including transitive dependencies.
What it is
python-utcp is the python implementation of UTCP. Prior to 1.1.3, the substituteutcpargs method in clicommunicationprotocol.py inserts user-controlled toolargs values directly into shell command strings without any sanitization or escaping. These commands are then executed via /bin/bash -c (Unix) or powershell.exe -Command (Windows), allowing an attacker to inject arbitrary shell commands. This vulnerability is fixed in 1.1.3.
From the GitHub advisory
Summary
The substituteutcpargs method in clicommunicationprotocol.py inserts user-controlled toolargs values directly into shell command strings without any sanitization or escaping. These commands are then executed via /bin/bash -c (Unix) or powershell.exe -Command (Windows), allowing an attacker to inject arbitrary shell commands.
Affected File
plugins/communicationprotocols/cli/src/utcpcli/clicommunicationprotocol.py
Vulnerable Code
Weakness type: CWE-78.
Product: utcp-cli (PyPI) · Assigned by: GitHub_M · Published: 2026-05-14
Affected and fixed versions
| Ecosystem | Package | Vulnerable | First fixed |
|---|---|---|---|
| PyPI | utcp-cli | <= 1.1.1 | 1.1.2 |
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| universal-tool-calling-protocol | python-utcp | < 1.1.2 |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_M | 3.1 | 8.3 High | CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H |
| GitHub | 3.1 | 10.0 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H |
- Attack vector: network (remotely reachable)
- Attack complexity: high (needs special conditions)
- Privileges required: none (no login)
- User interaction: required (a user must click/open something)
- Scope: changed (can affect other components)
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc, automatable no, technical impact total.
- FIRST EPSS (model of 2026-10-21): 0.35% probability of exploitation activity in the next 30 days; percentile 28.
Timeline
- — CVE record published by GitHub_M
- — GitHub-reviewed advisory GHSA-33p6-5jxp-p3x4 published (critical)
- — CVE record last updated
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vulnerability records
- GitHub Advisory GHSA-33p6-5jxp-p3x4 github.com
- CVE.org record CVE-2026-45369 cve.org
- NVD entry CVE-2026-45369 nvd.nist.gov
Other references from the CVE record and advisory
- github.com github.com