An Apache HTTP Server security update has been released for Ubuntu 18.04 LTS, 20.04 LTS, and 21.10.

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Ubuntu Security Notice USN-5333-1
March 17, 2022

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

- Ubuntu 21.10
- Ubuntu 20.04 LTS
- Ubuntu 18.04 LTS

Summary:

Several security issues were fixed in Apache HTTP Server.

Software Description:
- apache2: Apache HTTP server

Details:

Chamal De Silva discovered that the Apache HTTP Server mod_lua module
incorrectly handled certain crafted request bodies. A remote attacker could
possibly use this issue to cause the server to crash, resulting in a denial
of service. (CVE-2022-22719)

James Kettle discovered that the Apache HTTP Server incorrectly closed
inbound connection when certain errors are encountered. A remote attacker
could possibly use this issue to perform an HTTP Request Smuggling attack.
(CVE-2022-22720)

It was discovered that the Apache HTTP Server incorrectly handled large
LimitXMLRequestBody settings on certain platforms. In certain
configurations, a remote attacker could use this issue to cause the server
to crash, resulting in a denial of service, or possibly execute arbitrary
code. (CVE-2022-22721)

Ronald Crane discovered that the Apache HTTP Server mod_sed module
incorrectly handled memory. A remote attacker could use this issue to cause
the server to crash, resulting in a denial of service, or possibly execute
arbitrary code. (CVE-2022-23943)

Update instructions:

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

Ubuntu 21.10:
apache2 2.4.48-3.1ubuntu3.3
apache2-bin 2.4.48-3.1ubuntu3.3

Ubuntu 20.04 LTS:
apache2 2.4.41-4ubuntu3.10
apache2-bin 2.4.41-4ubuntu3.10

Ubuntu 18.04 LTS:
apache2 2.4.29-1ubuntu4.22
apache2-bin 2.4.29-1ubuntu4.22

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

References:
  https://ubuntu.com/security/notices/USN-5333-1
CVE-2022-22719, CVE-2022-22720, CVE-2022-22721, CVE-2022-23943

Package Information:
  https://launchpad.net/ubuntu/+source/apache2/2.4.48-3.1ubuntu3.3
  https://launchpad.net/ubuntu/+source/apache2/2.4.41-4ubuntu3.10
  https://launchpad.net/ubuntu/+source/apache2/2.4.29-1ubuntu4.22