Off-by-one error in passwd 0.68 and earlier, when using the --stdin option, causes passwd to use the first 78 characters of a password instead of the first 79, which results in a small reduction of the search space required for brute force attacks.
https://exchange.xforce.ibmcloud.com/vulnerabilities/16178
http://www.securityfocus.com/bid/10370
http://www.mandriva.com/security/advisories?name=MDKSA-2004:045