USN-1221-1: Mutt vulnerability

29 September 2011

mutt vulnerability

A security issue affects these releases of Ubuntu and its derivatives:

  • Ubuntu 11.04
  • Ubuntu 10.10
  • Ubuntu 10.04 LTS


An attacker could trick mutt into trusting a rogue server.

Software Description

  • mutt - text-based mailreader supporting MIME, GPG, PGP and threading


It was discovered that mutt incorrectly verified the hostname in an SSL certificate. An attacker could trick mutt into trusting a rogue SMTPS, IMAPS, or POP3S server’s certificate, which was signed by a trusted certificate authority, to perform a man-in-the-middle attack.

Update instructions

The problem can be corrected by updating your system to the following package versions:

Ubuntu 11.04
mutt - 1.5.21-2ubuntu3.1
mutt-patched - 1.5.21-2ubuntu3.1
Ubuntu 10.10
mutt - 1.5.20-9ubuntu2.1
mutt-patched - 1.5.20-9ubuntu2.1
Ubuntu 10.04 LTS
mutt - 1.5.20-7ubuntu1.1
mutt-patched - 1.5.20-7ubuntu1.1

To update your system, please follow these instructions:

After a standard system update you need to restart mutt to make all the necessary changes. Users are encouraged to verify their ~/.mutt_certificates file to ensure only trusted certificates are listed.