Buffer overflow in the lex routines of nslookup for AIX 4.3 may allow attackers to cause a core dump and possibly execute arbitrary code via "long input strings."
https://exchange.xforce.ibmcloud.com/vulnerabilities/7867
http://www.kb.cert.org/vuls/id/182777
http://www-1.ibm.com/support/search.wss?rs=0&q=IX79909&apar=only