By using an invalid transfer-encoding header, an attacker could smuggle an HTTP response.
Originally reported by @ZeddYu, who has our thanks for the detailed report.
The problem has been fixed in Puma 3.12.5 and Puma 4.3.4.
If you have any questions or comments about this advisory:
{
"github_reviewed_at": "2020-05-22T14:40:36Z",
"severity": "HIGH",
"github_reviewed": true,
"cwe_ids": [
"CWE-444"
],
"nvd_published_at": "2020-05-22T15:15:00Z"
}