apache -- ap_resolve_env buffer overflow

SITIC discovered a vulnerability in Apache 2’s handling of
environmental variable settings in the httpd configuration
files (the main httpd.conf' and .htaccess’ files).
According to a SITIC advisory:

The buffer overflow occurs when expanding ${ENVVAR}
constructs in .htaccess or httpd.conf files. The function
ap_resolve_env() in server/util.c copies data from
environment variables to the character array tmp with
strcat(3), leading to a buffer overflow.