The mirroring support (-M, --use-mirrors) in Python Pip before 1.5 uses insecure DNS querying and authenticity checks which allows attackers to perform man-in-the-middle attacks.
{
    "nvd_published_at": "2019-11-05T22:15:00Z",
    "severity": "HIGH",
    "github_reviewed_at": "2022-07-07T23:28:34Z",
    "github_reviewed": true,
    "cwe_ids": [
        "CWE-287"
    ]
}