suspicious-eval-usage (S307)

Derived from the flake8-bandit linter.

What it does

Checks for uses of the builtin eval() function.

Why is this bad?

The eval() function is insecure as it enables arbitrary code execution.

If you need to evaluate an expression from a string, consider using ast.literal_eval() instead, which will raise an exception if the expression is not a valid Python literal.

Example

x = eval(input("Enter a number: "))

Use instead:

from ast import literal_eval

x = literal_eval(input("Enter a number: "))

References

• Python documentation: eval
• Python documentation: literal_eval
• Eval really is dangerous by Ned Batchelder