Multiple format string vulnerabilities in the SSI filter in Xitami Web Server 2.5c2, and possibly other versions, allow remote attackers to cause a denial of service (daemon crash) and possibly execute arbitrary code via format string specifiers in a URI that ends in (1) .ssi, (2) .shtm, or (3) .shtml, which triggers incorrect logging code involving the sendfmt function in the SMT kernel.