CVE-2016-2569: Squid-Cache Squid

High severity, CVSS 7.5. EPSS: 31.2% chance of exploitation in the next 30 days.

Squid 3.x before 3.5.15 and 4.x before 4.0.7 does not properly append data to String objects, which allows remote servers to cause a denial of service (assertion failure and daemon exit) via a long string, as demonstrated by a crafted HTTP Vary header.

Affected products

• Squid-Cache Squid: version 3.0 only; version 3.0.stable1 only; version 3.0.stable2 only; version 3.0.stable3 only; version 3.0.stable4 only; version 3.0.stable5 only; …

Published 2016-02-27. Last modified 2026-06-17.