Input validation error in Varnish Cache - CVE-2020-11653

Vulnerability identifier: #VU30310

CSH Severity: Medium

CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2020-11653

CWE-ID: CWE-20

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote non-authenticated attacker to perform a denial of service (DoS) attack.

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.

Varnish Cache
Red Hat Enterprise Linux for x86_64
Red Hat Enterprise Linux for IBM z Systems
Red Hat Enterprise Linux for Power, little endian
Red Hat Enterprise Linux for ARM 64
SUSE Linux
Opensuse
Ubuntu
varnish (Ubuntu package)
libvarnishapi1 (Ubuntu package)
libvarnishapi2 (Ubuntu package)

Install update from vendor's website.

Varnish Cache - update to 6.0.6
varnish (Ubuntu package) - addressed in versions 5.2.1-1ubuntu0.1, 6.2.1-2ubuntu0.1, 6.2.1-2ubuntu0.2, 6.5.2-1ubuntu0.2, 6.6.1-1ubuntu0.2
libvarnishapi1 (Ubuntu package) - update to 5.2.1-1ubuntu0.1
libvarnishapi2 (Ubuntu package) - addressed in versions 6.2.1-2ubuntu0.1, 6.2.1-2ubuntu0.2, 6.5.2-1ubuntu0.2, 6.6.1-1ubuntu0.2

• http://lists.opensuse.org/opensuse-security-announce/2020-06/msg00026.html
• http://lists.opensuse.org/opensuse-security-announce/2020-06/msg00031.html
• https://varnish-cache.org/security/VSV00005.html#vsv00005

• Input validation error in Varnish Cache
• OpenSUSE Linux update for varnish
• OpenSUSE Linux update for varnish
• Red Hat Enterprise Linux 8 update for the varnish:6 module
• Ubuntu update for varnish
• Ubuntu update for varnish