PYSEC-2026-2915 
### 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)`](/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__`:

```python
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:

```python
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)`](/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`:

```python
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)`](/Users/shmulc/Documents/Codex/2026-05-03/please-go-over-tmp-tp-advisories/repos/PraisonAI/src/praisonai-agents/praisonaiagents/agent/agent.py:1749):

```python
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)`](/Users/shmulc/Documents/Codex/2026-05-03/please-go-over-tmp-tp-advisories/repos/PraisonAI/src/praisonai-agents/tests/unit/[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:142):56) asserts that a default `Agent` has `_perm_allow is None`.
- [`test_permissions.py`](/Users/shmulc/Documents/Codex/2026-05-03/please-go-over-tmp-tp-advisories/repos/PraisonAI/src/praisonai-agents/tests/unit/test_permissions.py:142) 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:

```bash
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**
```text
{'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.
CVSS v3.1 score: 8.6