[USN-4994-1] Apache HTTP Server vulnerabilities

========================================================================== Ubuntu Security Notice USN-4994-1 June 21, 2021
apache2 vulnerabilities ==========================================================================
A security issue affects these releases of Ubuntu and its derivatives:
– Ubuntu 21.04 – Ubuntu 20.10 – 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:
Marc Stern discovered that the Apache mod_proxy_http module incorrectly handled certain requests. A remote attacker could possibly use this issue to cause Apache to crash, resulting in a denial of service. This issue only affected Ubuntu 20.04 LTS, Ubuntu 20.10, and Ubuntu 21.04. (CVE-2020-13950)
Antonio Morales discovered that the Apache mod_auth_digest module incorrectly handled certain Digest nonces. A remote attacker could possibly use this issue to cause Apache to crash, resulting in a denial of service. (CVE-2020-35452)
Antonio Morales discovered that the Apache mod_session module incorrectly handled certain Cookie headers. A remote attacker could possibly use this issue to cause Apache to crash, resulting in a denial of service. (CVE-2021-26690)
Christophe Jaillet discovered that the Apache mod_session module incorrectly handled certain SessionHeader values. A remote attacker could use this issue to cause Apache to crash, resulting in a denial of service, or possibly execute arbitrary code. (CVE-2021-26691)
Christoph Anton Mitterer discovered that the new MergeSlashes configuration option resulted in unexpected behaviour in certain situations. (CVE-2021-30641)
Update instructions:
The problem can be corrected by updating your system to the following package versions:
Ubuntu 21.04: apache2 2.4.46-4ubuntu1.1 apache2-bin 2.4.46-4ubuntu1.1
Ubuntu 20.10: apache2 2.4.46-1ubuntu1.2 apache2-bin 2.4.46-1ubuntu1.2
Ubuntu 20.04 LTS: apache2 2.4.41-4ubuntu3.3 apache2-bin 2.4.41-4ubuntu3.3
Ubuntu 18.04 LTS: apache2 2.4.29-1ubuntu4.16 apache2-bin 2.4.29-1ubuntu4.16
In general, a standard system update will make all the necessary changes.
References: ubuntu.com/security/notices/USN-4994-1 CVE-2020-13950, CVE-2020-35452, CVE-2021-26690, CVE-2021-26691, CVE-2021-30641
Package Information: launchpad.net/ubuntu/+source/apache2/2.4.46-4ubuntu1.1 launchpad.net/ubuntu/+source/apache2/2.4.46-1ubuntu1.2 launchpad.net/ubuntu/+source/apache2/2.4.41-4ubuntu3.3 launchpad.net/ubuntu/+source/apache2/2.4.29-1ubuntu4.16