USN-5090-4: Apache HTTP Server regression

Releases

• Ubuntu 16.04 ESM

Packages

• apache2 - Apache HTTP server

Details

USN-5090-1 fixed vulnerabilities in Apache HTTP Server. One of the upstream
fixes introduced a regression in UDS URIs. This update fixes the problem.

Original advisory details:

James Kettle discovered that the Apache HTTP Server HTTP/2 module
incorrectly handled certain crafted methods. A remote attacker could
possibly use this issue to perform request splitting or cache poisoning
attacks. (CVE-2021-33193)

It was discovered that the Apache HTTP Server incorrectly handled certain
malformed requests. A remote attacker could possibly use this issue to
cause the server to crash, resulting in a denial of service.
(CVE-2021-34798)

Li Zhi Xin discovered that the Apache mod_proxy_uwsgi module incorrectly
handled certain request uri-paths. A remote attacker could possibly use
this issue to cause the server to crash, resulting in a denial of service.
This issue only affected Ubuntu 20.04 LTS and Ubuntu 21.04.
(CVE-2021-36160)

It was discovered that the Apache HTTP Server incorrectly handled escaping
quotes. If the server was configured with third-party modules, 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-2021-39275)

It was discovered that the Apache mod_proxy module incorrectly handled
certain request uri-paths. A remote attacker could possibly use this issue
to cause the server to forward requests to arbitrary origin servers.
(CVE-2021-40438)

Update instructions

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

Ubuntu 16.04

• apache2 - 2.4.18-2ubuntu3.17+esm3
  Available with Ubuntu Pro
• apache2-bin - 2.4.18-2ubuntu3.17+esm3
  Available with Ubuntu Pro

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

References

• https://launchpad.net/bugs/1945311