The remote host is missing an update as announced via advisory SSA:2003-336-01.
New kernels are available for Slackware 9.1 and -current. These have been upgraded to Linux kernel version 2.4.23, which fixes a bug in the kernel's do_brk() function that could be exploited to gain root privileges. These updated kernels and modules should be installed by any sites running a 2.4 kernel earlier than 2.4.23. Linux 2.0 and 2.2 kernels are not vulnerable. More details about the Apache issue may be found in the Common Vulnerabilities and Exposures (CVE) database: http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2003-0961