The remote host is missing an update as announced via advisory SSA:2004-133-01.

https://secure1.securityspace.com/smysecure/catid.html?in=SSA:2004-133-01

New apache packages are available for Slackware 8.1, 9.0, 9.1, and -current to fix security issues. These include a possible denial-of-service attack as well as the ability to possible pipe shell escapes through Apache's errorlog (which could create an exploit if the error log is read in a terminal program that does not filter such escapes). We recommend that sites running Apache upgrade to the new Apache package. More details about these issues may be found in the Common Vulnerabilities and Exposures (CVE) database: http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2003-0987 http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2003-0020 http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2004-0174 http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2003-0993