An issue was discovered in Varnish Cache before 6.0.6 LTS, 6.1.x and 6.2.x before 6.2.3, and 6.3.x before 6.3.2. It occurs when communication with a TLS termination proxy uses PROXY version 2. There can be an assertion failure and daemon restart, which causes a performance loss.

Affected: Ubuntu:18.04:LTS: varnish, Ubuntu:20.04:LTS: varnish, Ubuntu:22.04:LTS: varnish

It was dicovered that Varnish Cache did not clear a pointer between the handling of one client request and the next request within the same connection. A remote attacker could possibly use this issue to obtain sensitive information. (CVE-2019-20637)

It was discovered that Varnish Cache could have an assertion failure when a TLS termination proxy uses PROXY version 2. A remote attacker could possibly use this issue to restart the daemon and cause a performance loss. (CVE-2020-11653)

It was discovered that Varnish Cache allowed request smuggling and VCL authorization bypass via a large Content-Length header for a POST request. A remote attacker could possibly use this issue to obtain sensitive information. (CVE-2021-36740)

It was discovered that Varnish Cache allowed request smuggling for HTTP/1 connections. A remote attacker could possibly use this issue to obtain sensitive information. (CVE-2022-23959)