Last evening I meant do do some routine updates on some Unix (FreeBSD) servers I maintain. A new version of libpng had been released so I installed it. Then I recompiled PHP with some parameter changes. Suddenly apache web server on one of the systems started putting out just heaps of text. On closer inspection it turned out to be content of the mime ‘magic’ file that is found in the apache configuration directory. WHAT was going ON?! There were also garbled characters in the end of the "Server Version" line of httpdinfo, around where OpenSSL version info would usually be displayed.
Few web searches later I came across a bug report which shed light on what was happening. I had upgraded the server to apache httpd 2.2.6 some time ago, but since the garbled characters are probably created from other information that is dependant on the server configuration, the bug "activated" when I changed the configuration slightly. My guess is that as the result of the configuration change the server header on the affected server came to include a line feed or some other disruptive control character that mauled the response header when a client was requesting content.
I resolved the problem by reverting to the previous released version. It’s odd that while the bug report (which can also be found elsewhere on the web) considers this a critical bug the released version remains the same even though this has been fixed in the SVN. So if you download 2.2.6 and install it using mod_ssl statically, you may run into trouble brought on by this bug.