Updated Apache2 packages has been released for Ubuntu Linux 19.04, 18.04 LTS, and 16.04 LTS

=========================================================================
Ubuntu Security Notice USN-4113-2
September 17, 2019

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

- Ubuntu 19.04
- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS

Summary:

USN-4113-1 introduced a regression in Apache.

Software Description:
- apache2: Apache HTTP server

Details:

USN-4113-1 fixed vulnerabilities in the Apache HTTP server.
Unfortunately, that update introduced a regression when proxying
balancer manager connections in some configurations. This update
fixes the problem.

We apologize for the inconvenience.

Original advisory details:

Stefan Eissing discovered that the HTTP/2 implementation in Apache
did not properly handle upgrade requests from HTTP/1.1 to HTTP/2 in
some situations. A remote attacker could use this to cause a denial
of service (daemon crash). This issue only affected Ubuntu 18.04 LTS
and Ubuntu 19.04. (CVE-2019-0197)

Craig Young discovered that a memory overwrite error existed in
Apache when performing HTTP/2 very early pushes in some situations. A
remote attacker could use this to cause a denial of service (daemon
crash). This issue only affected Ubuntu 18.04 LTS and Ubuntu 19.04.
(CVE-2019-10081)

Craig Young discovered that a read-after-free error existed in the
HTTP/2 implementation in Apache during connection shutdown. A remote
attacker could use this to possibly cause a denial of service (daemon
crash) or possibly expose sensitive information. This issue only
affected Ubuntu 18.04 LTS and Ubuntu 19.04. (CVE-2019-10082)

Matei Badanoiu discovered that the mod_proxy component of
Apache did not properly filter URLs when reporting errors in some
configurations. A remote attacker could possibly use this issue to
conduct cross-site scripting (XSS) attacks. (CVE-2019-10092)

Daniel McCarney discovered that mod_remoteip component of Apache
contained a stack buffer overflow when parsing headers from a trusted
intermediary proxy in some situations. A remote attacker controlling a
trusted proxy could use this to cause a denial of service or possibly
execute arbitrary code. This issue only affected Ubuntu 19.04.
(CVE-2019-10097)

Yukitsugu Sasaki discovered that the mod_rewrite component in Apache
was vulnerable to open redirects in some situations. A remote attacker
could use this to possibly expose sensitive information or bypass
intended restrictions. (CVE-2019-10098)

Jonathan Looney discovered that the HTTP/2 implementation in Apache did
not properly limit the amount of buffering for client connections in
some situations. A remote attacker could use this to cause a denial
of service (unresponsive daemon). This issue only affected Ubuntu
18.04 LTS and Ubuntu 19.04. (CVE-2019-9517)

Update instructions:

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

Ubuntu 19.04:
apache2 2.4.38-2ubuntu2.3
apache2-bin 2.4.38-2ubuntu2.3

Ubuntu 18.04 LTS:
apache2 2.4.29-1ubuntu4.11
apache2-bin 2.4.29-1ubuntu4.11

Ubuntu 16.04 LTS:
apache2 2.4.18-2ubuntu3.13
apache2-bin 2.4.18-2ubuntu3.13

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

References:
https://usn.ubuntu.com/4113-2
https://usn.ubuntu.com/4113-1
https://launchpad.net/bugs/1842701

Package Information:
https://launchpad.net/ubuntu/+source/apache2/2.4.38-2ubuntu2.3
https://launchpad.net/ubuntu/+source/apache2/2.4.29-1ubuntu4.11
https://launchpad.net/ubuntu/+source/apache2/2.4.18-2ubuntu3.13

  Apache HTTP Server Regression Update for Ubuntu Linux