In Pallets Jinja before 2.8.1, str.format allows a sandbox escape.
{ "cwe_ids": [ "CWE-134" ], "github_reviewed_at": "2020-06-16T21:40:24Z", "github_reviewed": true, "nvd_published_at": null, "severity": "HIGH" }
"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2019/04/GHSA-hj2j-77xm-mc5v/GHSA-hj2j-77xm-mc5v.json"