CVE-2021-37147: Apache Traffic Server

High severity, CVSS 7.5. EPSS: 2.5% chance of exploitation in the next 30 days.

Improper input validation vulnerability in header parsing of Apache Traffic Server allows an attacker to smuggle requests. This issue affects Apache Traffic Server 8.0.0 to 8.1.2 and 9.0.0 to 9.1.0.

Affected products

• Apache Traffic Server: from 8.0.0, up to and including 8.1.2; from 9.0.0, up to and including 9.1.0
• Debian Debian Linux: version 10.0 only; version 11.0 only

Published 2021-11-03. Last modified 2026-06-17.