CVE-2026-113717 is a vulnerability in virtualenv's pip seeder when used with the --download option. The issue arises because the pip seeder downloads bundled wheels with download=False, skipping virtualenv's wheel digest verification. This allows an attacker controlling a package index to serve a modified pip wheel that virtualenv installs without verifying its integrity. Both --seeder pip and --download options must be enabled for exploitation. A fix is available in virtualenv version 1.18.1_2.