Any ElGamal sign+encrypt keys created by GnuPG contain a cryptographic weakness that may allow someone to obtain the private key. These keys should be considered unusable and should be revoked.

The following summary was written by Werner Koch, GnuPG author:

Phong Nguyen identified a severe bug in the way GnuPG creates and uses ElGamal keys for signing. This is a significant security failure which can lead to a compromise of almost all ElGamal keys used for signing. Note that this is a real world vulnerability which will reveal your private key within a few seconds.

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Please take immediate action and revoke your ElGamal signing keys. Furthermore you should take whatever measures necessary to limit the damage done for signed or encrypted documents using that key.

Note that the standard keys as generated by GnuPG (DSA and ElGamal encryption) as well as RSA keys are NOT vulnerable. Note also that ElGamal signing keys cannot be generated without the use of a special flag to enable hidden options and even then overriding a warning message about this key type. See below for details on how to identify vulnerable keys.

A programming error in BIND 8 named can result in a DNS message being incorrectly cached as a negative response. As a result, an attacker may arrange for malicious DNS messages to be delivered to a target name server, and cause that name server to cache a negative response for some target domain name. The name server would thereafter respond negatively to legitimate queries for that domain name, resulting in a denial-of-service for applications that require DNS.

Mathopd contains a buffer overflow in the prepare_reply() function that may be remotely exploitable.

A buffer overflow exists in lftp which may be triggered when requesting a directory listing from a malicious server over HTTP.

An authenticated user may trigger a format string vulnerability present in qpopper's UIDL code, resulting in arbitrary code execution with group ID `mail' privileges.

Fetchmail can be crashed by a malicious email message.

Applications utilizing pam_smb can be compromised by any user who can enter a password. In many cases, this is a remote root compromise.

libmcrypt does incomplete input validation, leading to several buffer overflows. Additionally, a memory leak is present. Both of these problems may be exploited in a denial-of-service attack.