suspicious-xmle-tree-usage (S320)

Derived from the flake8-bandit linter.

What it does

Checks for uses of insecure XML parsers.

Why is this bad?

Many XML parsers are vulnerable to XML attacks (such as entity expansion), which cause excessive memory and CPU usage by exploiting recursion. An attacker could use such methods to access unauthorized resources.

Example

from lxml import etree

content = etree.parse("untrusted.xml")

References

• PyPI: lxml
• Common Weakness Enumeration: CWE-400
• Common Weakness Enumeration: CWE-776