An Apache HTTP Server security update has been released for Ubuntu Linux 16.04 ESM.

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Ubuntu Security Notice USN-5834-1
January 31, 2023

apache2 vulnerabilities
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 16.04 ESM

Summary:

Several security issues were fixed in Apache HTTP Server.

Software Description:
- apache2: Apache HTTP server

Details:

It was discovered that the Apache HTTP Server mod_dav module did not
properly handle specially crafted request headers. A remote attacker
could possibly use this issue to cause the process to crash, leading
to a denial of service. (CVE-2006-20001)

It was discovered that the Apache HTTP Server mod_proxy_ajp module did not
properly handle certain invalid Transfer-Encoding headers. A remote attacker
could possibly use this issue to perform an HTTP Request Smuggling attack.
(CVE-2022-36760)

Update instructions:

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

Ubuntu 16.04 ESM:
apache2 2.4.18-2ubuntu3.17+esm8
apache2-bin 2.4.18-2ubuntu3.17+esm8

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

References:
https://ubuntu.com/security/notices/USN-5834-1
CVE-2006-20001, CVE-2022-36760