USN-802-2: Apache regression

Ubuntu Security Notice USN-802-2

19th August, 2009

apache2 regression

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

  • Ubuntu 9.04
  • Ubuntu 8.10
  • Ubuntu 8.04 LTS
  • Ubuntu 6.06 LTS

Software description

  • apache2


USN-802-1 fixed vulnerabilities in Apache. The upstream fix for
CVE-2009-1891 introduced a regression that would cause Apache children to
occasionally segfault when mod_deflate is used. This update fixes the

We apologize for the inconvenience.

Original advisory details:

It was discovered that mod_proxy_http did not properly handle a large
amount of streamed data when used as a reverse proxy. A remote attacker
could exploit this and cause a denial of service via memory resource
consumption. This issue affected Ubuntu 8.04 LTS, 8.10 and 9.04.

It was discovered that mod_deflate did not abort compressing large files
when the connection was closed. A remote attacker could exploit this and
cause a denial of service via CPU resource consumption. (CVE-2009-1891)

Update instructions

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

Ubuntu 9.04:
apache2-mpm-worker 2.2.11-2ubuntu2.3
apache2-mpm-event 2.2.11-2ubuntu2.3
apache2.2-common 2.2.11-2ubuntu2.3
apache2-mpm-prefork 2.2.11-2ubuntu2.3
Ubuntu 8.10:
apache2-mpm-worker 2.2.9-7ubuntu3.3
apache2-mpm-event 2.2.9-7ubuntu3.3
apache2.2-common 2.2.9-7ubuntu3.3
apache2-mpm-prefork 2.2.9-7ubuntu3.3
Ubuntu 8.04 LTS:
apache2-mpm-worker 2.2.8-1ubuntu0.11
apache2-mpm-event 2.2.8-1ubuntu0.11
apache2.2-common 2.2.8-1ubuntu0.11
apache2-mpm-prefork 2.2.8-1ubuntu0.11
apache2-mpm-perchild 2.2.8-1ubuntu0.11
Ubuntu 6.06 LTS:
apache2-mpm-worker 2.0.55-4ubuntu2.8
apache2-mpm-perchild 2.0.55-4ubuntu2.8
libapr0 2.0.55-4ubuntu2.8
apache2-mpm-prefork 2.0.55-4ubuntu2.8
apache2-common 2.0.55-4ubuntu2.8

To update your system, please follow these instructions:

In general, a standard system upgrade is sufficient to effect the
necessary changes.


LP: 409987