This update for enigmail to version 1.9.9 fixes the following issues (boo#1073858):

* Enigmail could be coerced to use a malicious PGP public key with a corresponding secret key controlled by an attacker
* Enigmail could have replayed encrypted content in partially encrypted e-mails, allowing a plaintext leak
* Enigmail could be tricked into displaying incorrect signature verification results
* Specially crafted content may cause denial of service