CVE-2020-11653

Name: CVE-2020-11653
Creator: NVD / NIST
Published: 2020-04-08T23:15:12.73+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 2.11%

Last modified Jun 17, 2026

CVE-2020-11653 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. 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. EPSS estimates a 2.11% chance of exploitation in the next 30 days.

Description

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.

Metrics

CVSS 3.1

7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Probability

2.11%

79.4th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-617

Affected Software

Vendor	Product	Versions	Update
Varnish-Cache	Varnish Cache	>= 6.1.0, < 6.2.3	—
Varnish-Cache	Varnish Cache	>= 6.3.0, < 6.3.2	—
Varnish-Software	Varnish Cache	>= 6.0.0, < 6.0.6	—
Opensuse	Backports Sle	15.0	Sp1
Opensuse	Leap	15.1	—
Debian	Debian Linux	10.0	—

References

http://lists.opensuse.org/opensuse-security-announce/2020-06/msg00026.htmlMailing List, Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2020-06/msg00031.htmlMailing List, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2022/11/msg00036.htmlMailing List, Third Party Advisory
https://varnish-cache.org/security/VSV00005.html#vsv00005Vendor Advisory
http://lists.opensuse.org/opensuse-security-announce/2020-06/msg00026.htmlMailing List, Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2020-06/msg00031.htmlMailing List, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2022/11/msg00036.htmlMailing List, Third Party Advisory
https://varnish-cache.org/security/VSV00005.html#vsv00005Vendor Advisory

Timeline

Published: Apr 8, 2020
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-11653?

How severe is CVE-2020-11653?

CVE-2020-11653 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 2.11% probability of exploitation in the next 30 days.

How do I fix CVE-2020-11653?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2020-11653?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST