---
title: "CVE-2020-11653\n    | Ubuntu"
description: Ubuntu is an open source software operating system that runs from the
  desktop, to the cloud, to all your internet connected things.
url: https://ubuntu.com/security/CVE-2020-11653?format=md
keywords: index, follow
---

# CVE-2020-11653

Publication date 8 April 2020

Last updated 25 August 2025

---

Ubuntu priority

**Low**

[Why this priority?](https://ubuntu.com/security/cves/about#priority )

## Cvss 3 Severity Score

**7.5 · High**

[Score breakdown](https://ubuntu.com/security/CVE-2020-11653?format=md#impact-score)

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## 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.

## Status

Show unmaintained releases

| Package | Ubuntu Release | Status |
| --- | --- | --- |
| varnish | 22.04 LTS jammy | Not affected |
| 21.10 impish | Not affected |
| 21.04 hirsute | Not affected |
| 20.10 groovy | Not affected |
| 20.04 LTS focal | Fixed 6.2.1-2ubuntu0.1 |
| 19.10 eoan | Ignored end of life |
| 18.04 LTS bionic | Not affected |
| 16.04 LTS xenial | Not affected |
| 14.04 LTS trusty | Not affected |

---

* [How can I get the fixes?](https://ubuntu.com/security/cves/about#security)
* [What do statuses mean?](https://ubuntu.com/security/cves/about#statuses)

## Severity score breakdown

CVSS version:
CVSS v3.0

**Base score**

7.5 · High

* Base metrics

  | Parameter | Value |
  | --- | --- |
  | Attack vector | Network |
  | Attack complexity | Low |
  | Privileges required | None |
  | User interaction | None |
  | Scope | Unchanged |
  | Confidentiality impact | None |
  | Integrity impact | None |
  | Availability impact | High |
* Scores

  | Parameter | Value |
  | --- | --- |
  | Base score | 7.5 · High |
  | Exploitability score | - |
  | Impact score | - |

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

## References

* [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-11653)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2020-11653)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2020-11653)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2020-11653)

### Related Ubuntu Security Notices (USN)

+ [USN-5474-1](https://usn.ubuntu.com/USN-5474-1)
+ Varnish Cache vulnerabilities
+ 8 June 2022

+ [USN-5474-2](https://usn.ubuntu.com/USN-5474-2)
+ Varnish Cache regression
+ 23 August 2022

### Other references

* <https://varnish-cache.org/security/VSV00005.html#vsv00005>
* <https://github.com/varnishcache/varnish-cache/commit/2d8fc1a784a1e26d78c30174923a2b14ee2ebf62>
* <https://www.cve.org/CVERecord?id=CVE-2020-11653>