The function gzprintf within zlib, when called with a string longer than Z_PRINTF_BUFZISE (= 4096 bytes), can overflow without giving a warning. zlib-1.1.4 and earlier exhibit this behavior. There are no known exploits of the gzprintf overrun, and only a few programs, including rpm2html and gimp-print, are known to use the gzprintf function. The problem has been fixed by checking the length of the output string within gzprintf. This is CAN-2003-0107 and will be RHSA-2003:081
Needinfo so I don't have to stare at the duplicate bug.
Fixed by http://rhn.redhat.com/errata/RHSA-2003-081.html