stunnel is a socket wrapper which can provide SSL support to ordinary applications. For example, it can be used in conjunction with imapd to create an SSL-secure IMAP server. An integer conversion issue was found in stunnel when using Microsoft NT LAN Manager authentication with the HTTP CONNECT tunneling method. With this configuration, and using stunnel in SSL client mode on a 64-bit system, an attacker could possibly execute arbitrary code with the privileges of the stunnel process via a man-in-the-middle attack or by tricking a user into using a malicious proxy. All stunnel users should upgrade to this updated package, which contains a backported patch to correct this issue.