mapserv in MapServer 4.x before 4.10.4 and 5.x before 5.2.2 allows remote attackers to read arbitrary invalid .map files via a full pathname in the map parameter, which triggers the display of partial file contents within an error message, as demonstrated by a /tmp/sekrut.map symlink.

More... (http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2009-0842)