CVE-2026-39888

PraisonAI is a multi-agent teams system. Prior to 1.5.115, execute_code() in praisonaiagents.tools.python_tools defaults to sandbox_mode="sandbox", which runs user code in a subprocess wrapped with a restricted builtins dict and an AST-based blocklist. The AST blocklist embedded inside the subprocess wrapper (blocked_attrs of python_tools.py) contains only 11 attribute names — a strict subset of the 30+ names blocked in the direct-execution path. The four attributes that form a frame-traversal chain out of the sandbox are all absent from the subprocess list (traceback, tb_frame, f_back, and f_builtins). Chaining these attributes through a caught exception exposes the real Python builtins dict of the subprocess wrapper frame, from which exec can be retrieved and called under a non-blocked variable name — bypassing every remaining security layer. This vulnerability is fixed in 1.5.115.

PraisonAI is a multi-agent teams system. Prior to 1.5.115, execute_code() in praisonaiagents.tools.python_tools defaults to sandbox_mode="sandbox", which runs user code in a subprocess wrapped with a restricted builtins dict and an AST-based blocklist. The AST blocklist embedded inside the subprocess wrapper (blocked_attrs of python_tools.py) contains only 11 attribute names — a strict subset of the 30+ names blocked in the direct-execution path. The four attributes that form a frame-traversal chain out of the sandbox are all absent from the subprocess list (traceback, tb_frame, f_back, and f_builtins). Chaining these attributes through a caught exception exposes the real Python builtins dict of the subprocess wrapper frame, from which exec can be retrieved and called under a non-blocked variable name — bypassing every remaining security layer. This vulnerability is fixed in 1.5.115.

Summary

execute_code() in praisonaiagents.tools.python_tools defaults to sandbox_mode="sandbox", which runs user code in a subprocess wrapped with a restricted __builtins__ dict and an AST-based blocklist. The AST blocklist embedded inside the subprocess wrapper (blocked_attrs, line 143 of python_tools.py) contains only 11 attribute names — a strict subset of the 30+ names blocked in the direct-execution path. The four attributes that form a frame-traversal chain out of the sandbox are all absent from the subprocess list:

| Attribute | In subprocess blocked_attrs | In direct-mode _blocked_attrs | |---|---|---| | __traceback__ | NO | YES | | tb_frame | NO | YES | | f_back | NO | YES | | f_builtins | NO | YES |

Chaining these attributes through a caught exception exposes the real Python builtins dict of the subprocess wrapper frame, from which exec can be retrieved and called under a non-blocked variable name — bypassing every remaining security layer.

Tested and confirmed on praisonaiagents 1.5.113 (latest), Python 3.10.

Severity

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H — 9.9 Critical

| Vector | Value | Rationale | |---|---|---| | AV:N | Network | execute_code is a designated agent tool; user/LLM-supplied code reaches it over the network in all standard deployments | | AC:L | Low | No race conditions or special configuration required | | PR:L | Low | Requires ability to submit code through an agent (typical end-user privilege) | | UI:N | None | No victim interaction | | S:C | Changed | Escapes subprocess sandbox into full host process context | | C:H | High | Arbitrary file read, environment variable access, credential exfiltration | | I:H | High | Arbitrary file write, arbitrary code execution on host | | A:H | High | Can terminate processes, exhaust resources |

Affected

• Package: praisonaiagents (PyPI)
• Affected versions: all versions shipping sandbox_mode="sandbox" (default since introduction) through 1.5.113
• Patched versions: none at time of report
• File: praisonaiagents/tools/python_tools.py

Root Cause

Two separate blocked_attrs sets — one much weaker than the other

_validate_code_ast() (line 39, used by direct mode) blocks 30+ attributes:

# python_tools.py line 52 — direct mode (FULL list, correctly includes frame attrs)
_blocked_attrs = frozenset({
    '__subclasses__', '__bases__', '__mro__', '__globals__',
    '__code__', '__class__', '__dict__', '__builtins__',
    '__import__', '__loader__', '__spec__', '__init_subclass__',
    '__set_name__', '__reduce__', '__reduce_ex__',
    '__traceback__', '__qualname__', '__module__',   # ← present here
    '__wrapped__', '__closure__', '__annotations__',
    'gi_frame', 'gi_code', 'cr_frame', 'cr_code',
    'ag_frame', 'ag_code', 'tb_frame', 'tb_next',    # ← present here
    'f_globals', 'f_locals', 'f_builtins', 'f_code', # ← present here
    'co_consts', 'co_names',
})

The subprocess wrapper script written to disk (line 143) uses a separate, inline blocked_attrs with only 11 entries — the frame-traversal attrs are missing:

# python_tools.py line 143 — subprocess wrapper (SHORT list, MISSING frame attrs)
blocked_attrs = {
    '__subclasses__', '__bases__', '__mro__', '__globals__',
    '__code__', '__class__', '__dict__', '__builtins__',
    '__import__', '__loader__', '__spec__'
    # __traceback__, tb_frame, f_back, f_builtins — all absent
}

_safe_getattr does not protect direct dot-notation access

_safe_getattr replaces the getattr builtin and blocks attribute names starting with _. However, it is only invoked when user code explicitly calls getattr(obj, name). Direct attribute access (obj.attr in source) uses Python's C-level tp_getattro slot and never passes through _safe_getattr. The AST check is therefore the only barrier to direct attribute…

PraisonAI is a multi-agent teams system. Prior to 1.5.115, execute_code() in praisonaiagents.tools.python_tools defaults to sandbox_mode="sandbox", which runs user code in a subprocess wrapped with a restricted builtins dict and an AST-based blocklist. The AST blocklist embedded inside the subprocess wrapper (blocked_attrs of python_tools.py) contains only 11 attribute names — a strict subset of the 30+ names blocked in the direct-execution path. The four attributes that form a frame-traversal chain out of the sandbox are all absent from the subprocess list (traceback, tb_frame, f_back, and f_builtins). Chaining these attributes through a caught exception exposes the real Python builtins dict of the subprocess wrapper frame, from which exec can be retrieved and called under a non-blocked variable name — bypassing every remaining security layer. This vulnerability is fixed in 1.5.115.

Summary

execute_code() in praisonaiagents.tools.python_tools defaults to sandbox_mode="sandbox", which runs user code in a subprocess wrapped with a restricted __builtins__ dict and an AST-based blocklist. The AST blocklist embedded inside the subprocess wrapper (blocked_attrs, line 143 of python_tools.py) contains only 11 attribute names — a strict subset of the 30+ names blocked in the direct-execution path. The four attributes that form a frame-traversal chain out of the sandbox are all absent from the subprocess list:

| Attribute | In subprocess blocked_attrs | In direct-mode _blocked_attrs | |---|---|---| | __traceback__ | NO | YES | | tb_frame | NO | YES | | f_back | NO | YES | | f_builtins | NO | YES |

Chaining these attributes through a caught exception exposes the real Python builtins dict of the subprocess wrapper frame, from which exec can be retrieved and called under a non-blocked variable name — bypassing every remaining security layer.

Tested and confirmed on praisonaiagents 1.5.113 (latest), Python 3.10.

Severity

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H — 9.9 Critical

| Vector | Value | Rationale | |---|---|---| | AV:N | Network | execute_code is a designated agent tool; user/LLM-supplied code reaches it over the network in all standard deployments | | AC:L | Low | No race conditions or special configuration required | | PR:L | Low | Requires ability to submit code through an agent (typical end-user privilege) | | UI:N | None | No victim interaction | | S:C | Changed | Escapes subprocess sandbox into full host process context | | C:H | High | Arbitrary file read, environment variable access, credential exfiltration | | I:H | High | Arbitrary file write, arbitrary code execution on host | | A:H | High | Can terminate processes, exhaust resources |

Affected

• Package: praisonaiagents (PyPI)
• Affected versions: all versions shipping sandbox_mode="sandbox" (default since introduction) through 1.5.113
• Patched versions: none at time of report
• File: praisonaiagents/tools/python_tools.py

Root Cause

Two separate blocked_attrs sets — one much weaker than the other

_validate_code_ast() (line 39, used by direct mode) blocks 30+ attributes:

# python_tools.py line 52 — direct mode (FULL list, correctly includes frame attrs)
_blocked_attrs = frozenset({
    '__subclasses__', '__bases__', '__mro__', '__globals__',
    '__code__', '__class__', '__dict__', '__builtins__',
    '__import__', '__loader__', '__spec__', '__init_subclass__',
    '__set_name__', '__reduce__', '__reduce_ex__',
    '__traceback__', '__qualname__', '__module__',   # ← present here
    '__wrapped__', '__closure__', '__annotations__',
    'gi_frame', 'gi_code', 'cr_frame', 'cr_code',
    'ag_frame', 'ag_code', 'tb_frame', 'tb_next',    # ← present here
    'f_globals', 'f_locals', 'f_builtins', 'f_code', # ← present here
    'co_consts', 'co_names',
})

The subprocess wrapper script written to disk (line 143) uses a separate, inline blocked_attrs with only 11 entries — the frame-traversal attrs are missing:

# python_tools.py line 143 — subprocess wrapper (SHORT list, MISSING frame attrs)
blocked_attrs = {
    '__subclasses__', '__bases__', '__mro__', '__globals__',
    '__code__', '__class__', '__dict__', '__builtins__',
    '__import__', '__loader__', '__spec__'
    # __traceback__, tb_frame, f_back, f_builtins — all absent
}

_safe_getattr does not protect direct dot-notation access

_safe_getattr replaces the getattr builtin and blocks attribute names starting with _. However, it is only invoked when user code explicitly calls getattr(obj, name). Direct attribute access (obj.attr in source) uses Python's C-level tp_getattro slot and never passes through _safe_getattr. The AST check is therefore the only barrier to direct attribute…

Summary

execute_code() in praisonaiagents.tools.python_tools defaults to sandbox_mode="sandbox", which runs user code in a subprocess wrapped with a restricted __builtins__ dict and an AST-based blocklist. The AST blocklist embedded inside the subprocess wrapper (blocked_attrs, line 143 of python_tools.py) contains only 11 attribute names — a strict subset of the 30+ names blocked in the direct-execution path. The four attributes that form a frame-traversal chain out of the sandbox are all absent from the subprocess list:

| Attribute | In subprocess blocked_attrs | In direct-mode _blocked_attrs | |---|---|---| | __traceback__ | NO | YES | | tb_frame | NO | YES | | f_back | NO | YES | | f_builtins | NO | YES |

Chaining these attributes through a caught exception exposes the real Python builtins dict of the subprocess wrapper frame, from which exec can be retrieved and called under a non-blocked variable name — bypassing every remaining security layer.

Tested and confirmed on praisonaiagents 1.5.113 (latest), Python 3.10.

Severity

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H — 9.9 Critical

| Vector | Value | Rationale | |---|---|---| | AV:N | Network | execute_code is a designated agent tool; user/LLM-supplied code reaches it over the network in all standard deployments | | AC:L | Low | No race conditions or special configuration required | | PR:L | Low | Requires ability to submit code through an agent (typical end-user privilege) | | UI:N | None | No victim interaction | | S:C | Changed | Escapes subprocess sandbox into full host process context | | C:H | High | Arbitrary file read, environment variable access, credential exfiltration | | I:H | High | Arbitrary file write, arbitrary code execution on host | | A:H | High | Can terminate processes, exhaust resources |

Affected

• Package: praisonaiagents (PyPI)
• Affected versions: all versions shipping sandbox_mode="sandbox" (default since introduction) through 1.5.113
• Patched versions: none at time of report
• File: praisonaiagents/tools/python_tools.py

Root Cause

Two separate blocked_attrs sets — one much weaker than the other

_validate_code_ast() (line 39, used by direct mode) blocks 30+ attributes:

# python_tools.py line 52 — direct mode (FULL list, correctly includes frame attrs)
_blocked_attrs = frozenset({
    '__subclasses__', '__bases__', '__mro__', '__globals__',
    '__code__', '__class__', '__dict__', '__builtins__',
    '__import__', '__loader__', '__spec__', '__init_subclass__',
    '__set_name__', '__reduce__', '__reduce_ex__',
    '__traceback__', '__qualname__', '__module__',   # ← present here
    '__wrapped__', '__closure__', '__annotations__',
    'gi_frame', 'gi_code', 'cr_frame', 'cr_code',
    'ag_frame', 'ag_code', 'tb_frame', 'tb_next',    # ← present here
    'f_globals', 'f_locals', 'f_builtins', 'f_code', # ← present here
    'co_consts', 'co_names',
})

The subprocess wrapper script written to disk (line 143) uses a separate, inline blocked_attrs with only 11 entries — the frame-traversal attrs are missing:

# python_tools.py line 143 — subprocess wrapper (SHORT list, MISSING frame attrs)
blocked_attrs = {
    '__subclasses__', '__bases__', '__mro__', '__globals__',
    '__code__', '__class__', '__dict__', '__builtins__',
    '__import__', '__loader__', '__spec__'
    # __traceback__, tb_frame, f_back, f_builtins — all absent
}

_safe_getattr does not protect direct dot-notation access

_safe_getattr replaces the getattr builtin and blocks attribute names starting with _. However, it is only invoked when user code explicitly calls getattr(obj, name). Direct attribute access (obj.attr in source) uses Python's C-level tp_getattro slot and never passes through _safe_getattr. The AST check is therefore the only barrier to direct attribute…