USN-4356-1: Squid vulnerabilities

13 May 2020

squid, squid3 vulnerabilities

A security issue affects these releases of Ubuntu and its derivatives:

  • Ubuntu 20.04 LTS
  • Ubuntu 19.10
  • Ubuntu 18.04 LTS
  • Ubuntu 16.04 LTS


Several security issues were fixed in Squid.

Software Description

  • squid - Web proxy cache server
  • squid3 - Web proxy cache server


Jeriko One discovered that Squid incorrectly handled certain Edge Side Includes (ESI) responses. A malicious remote server could cause Squid to crash, possibly poison the cache, or possibly execute arbitrary code. (CVE-2019-12519, CVE-2019-12521)

It was discovered that Squid incorrectly handled the hostname parameter to cachemgr.cgi when certain browsers are used. A remote attacker could possibly use this issue to inject HTML or invalid characters in the hostname parameter. This issue only affected Ubuntu 16.04 LTS, Ubuntu 18.04 LTS, and Ubuntu 19.10. (CVE-2019-18860)

Clément Berthaux and Florian Guilbert discovered that Squid incorrectly handled Digest Authentication nonce values. A remote attacker could use this issue to replay nonce values, or possibly execute arbitrary code. (CVE-2020-11945)

Update instructions

The problem can be corrected by updating your system to the following package versions:

Ubuntu 20.04 LTS
squid - 4.10-1ubuntu1.1
Ubuntu 19.10
squid - 4.8-1ubuntu2.3
Ubuntu 18.04 LTS
squid - 3.5.27-1ubuntu1.6
Ubuntu 16.04 LTS
squid - 3.5.12-1ubuntu7.11

To update your system, please follow these instructions:

In general, a standard system update will make all the necessary changes.