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Ubuntu Security Notice USN-4458-1
August 13, 2020

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

- Ubuntu 20.04 LTS
- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS

Summary:

Several security issues were fixed in Apache HTTP Server.

Software Description:
- apache2: Apache HTTP server

Details:

Fabrice Perez discovered that the Apache mod_rewrite module incorrectly
handled certain redirects. A remote attacker could possibly use this issue
to perform redirects to an unexpected URL. (CVE-2020-1927)

Chamal De Silva discovered that the Apache mod_proxy_ftp module incorrectly
handled memory when proxying to a malicious FTP server. A remote attacker
could possibly use this issue to obtain sensitive information.
(CVE-2020-1934)

Felix Wilhelm discovered that the HTTP/2 implementation in Apache did not
properly handle certain Cache-Digest headers. A remote attacker could
possibly use this issue to cause Apache to crash, resulting in a denial of
service. This issue only affected Ubuntu 18.04 LTS and Ubuntu 20.04 LTS.
(CVE-2020-9490)

Felix Wilhelm discovered that the Apache mod_proxy_uwsgi module incorrectly
handled large headers. A remote attacker could use this issue to obtain
sensitive information or possibly execute arbitrary code. This issue only
affected Ubuntu 20.04 LTS. (CVE-2020-11984)

Felix Wilhelm discovered that the HTTP/2 implementation in Apache did not
properly handle certain logging statements. A remote attacker could
possibly use this issue to cause Apache to crash, resulting in a denial of
service. This issue only affected Ubuntu 18.04 LTS and Ubuntu 20.04 LTS.
(CVE-2020-11993)

Update instructions:

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

Ubuntu 20.04 LTS:
  apache2                         2.4.41-4ubuntu3.1
  apache2-bin                     2.4.41-4ubuntu3.1
  libapache2-mod-proxy-uwsgi      2.4.41-4ubuntu3.1

Ubuntu 18.04 LTS:
  apache2                         2.4.29-1ubuntu4.14
  apache2-bin                     2.4.29-1ubuntu4.14

Ubuntu 16.04 LTS:
  apache2                         2.4.18-2ubuntu3.17
  apache2-bin                     2.4.18-2ubuntu3.17

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

References:
  https://usn.ubuntu.com/4458-1
  CVE-2020-11984, CVE-2020-11993, CVE-2020-1927, CVE-2020-1934,
  CVE-2020-9490

Package Information:
  https://launchpad.net/ubuntu/+source/apache2/2.4.41-4ubuntu3.1
  https://launchpad.net/ubuntu/+source/apache2/2.4.29-1ubuntu4.14
  https://launchpad.net/ubuntu/+source/apache2/2.4.18-2ubuntu3.17