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Ubuntu Security Notice USN-6500-2
December 11, 2023

squid3 vulnerabilities
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 18.04 LTS (Available with Ubuntu Pro)
- Ubuntu 16.04 LTS (Available with Ubuntu Pro)

Summary:

Several security issues were fixed in Squid.

Software Description:
- squid3: Web proxy cache server

Details:

USN-6500-1 fixed several vulnerabilities in Squid. This update provides
the corresponding update for Ubuntu 16.04 LTS and Ubuntu 18.04 LTS.

Original advisory details:

 Joshua Rogers discovered that Squid incorrectly handled the Gopher
 protocol. A remote attacker could possibly use this issue to cause Squid to
 crash, resulting in a denial of service. Gopher support has been disabled
 in this update. (CVE-2023-46728)

 Joshua Rogers discovered that Squid incorrectly handled HTTP Digest
 Authentication. A remote attacker could possibly use this issue to cause
 Squid to crash, resulting in a denial of service. (CVE-2023-46847)

Update instructions:

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

Ubuntu 18.04 LTS (Available with Ubuntu Pro):
  squid                           3.5.27-1ubuntu1.14+esm1
  squid3                          3.5.27-1ubuntu1.14+esm1

Ubuntu 16.04 LTS (Available with Ubuntu Pro):
  squid                           3.5.12-1ubuntu7.16+esm2
  squid3                          3.5.12-1ubuntu7.16+esm2

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

References:
  https://ubuntu.com/security/notices/USN-6500-2
  https://ubuntu.com/security/notices/USN-6500-1
  CVE-2023-46728, CVE-2023-46847