It was discovered that krb5, a system for authenticating users and services on a network, is prone to integer underflow in the AES and RC4 decryption operations of the crypto library. A remote attacker can cause crashes, heap corruption, or, under extraordinarily unlikely conditions, arbitrary code execution. For the old stable distribution , this problem has been fixed in version 1.4.4-7etch8. For the stable distribution , this problem has been fixed in version 1.6.dfsg.4~beta1-5lenny2. For the testing distribution , this problem will be fixed soon. For the unstable distribution , this problem has been fixed in version 1.8+dfsg~alpha1-1. We recommend that you upgrade your krb5 package.