Heap-based buffer overflow in the array_push function in hashcash.c for Hashcash before 1.21 might allow attackers to execute arbitrary code via crafted entries.
https://exchange.xforce.ibmcloud.com/vulnerabilities/27422
http://www.vupen.com/english/advisories/2006/2551
http://www.securityfocus.com/bid/18659
http://www.hashcash.org/source/CHANGELOG
http://www.gentoo.org/security/en/glsa/glsa-200606-25.xml
http://www.debian.org/security/2006/dsa-1114
http://secunia.com/advisories/21146