In Pallets Jinja before 2.8.1, str.format allows a sandbox escape.
{
"cpe": "cpe:2.3:a:palletsprojects:jinja:*:*:*:*:*:*:*:*",
"extracted_events": [
{
"introduced": "0"
},
{
"fixed": "2.8.1"
}
],
"source": [
"CPE_FIELD",
"REFERENCES"
]
}