The Python Programming Language

Python provides memory safety by default, so low-level security vulnerabilities are rare and typically needs fixing the Python interpreter or standard library itself.

Other sections with Python-specific advice include:

Dangerous Standard Library Features

Some areas of the standard library, notably the ctypes module, do not provide memory safety guarantees comparable to the rest of Python. If such functionality is used, the advice in Defensive Coding in C should be followed.

Run-time Compilation and Code Generation

The following Python functions and statements related to code execution should be avoided:

  • compile

  • eval

  • exec

  • execfile

If you need to parse integers or floating point values, use the int and float functions instead of eval. Sandboxing untrusted Python code does not work reliably.


The rexec Python module cannot safely sandbox untrusted code and should not be used. The standard CPython implementation is not suitable for sandboxing.