It was discovered that Mutt, a text-based mailreader supporting MIME, GPG, PGP and threading, incorrectly handled certain input. An attacker could possibly use this issue to cause a crash, or expose sensitive information.
For Debian 8 jessie, these problems have been fixed in version 1.5.23-3+deb8u6.
We recommend that you upgrade your mutt packages.
Further information about Extended LTS security advisories can be found at: https://deb.freexian.com/extended-lts/