PHP Numeric Errors Vulnerability - CVE-2010-4699

The iconv_mime_decode_headers function in the Iconv extension in PHP before 5.3.4 does not properly handle encodings that are unrecognized by the iconv and mbstring (aka Multibyte String) implementations which allows remote attackers to trigger an incomplete output array and possibly bypass spam detection or have unspecified other impact via a crafted Subject header in an e-mail message as demonstrated by the ks_c_5601-1987 character set.