Evolution is the integrated collection of e-mail, calendaring, contact management, communications, and personal information management tools for the GNOME desktop environment. Evolution Data Server provides a unified back-end for applications which interact with contacts, task and calendar information. Evolution Data Server was originally developed as a back-end for Evolution, but is now used by multiple other applications. Evolution did not properly check the Secure/Multipurpose Internet Mail Extensions signatures used for public key encryption and signing of e-mail messages. An attacker could use this flaw to spoof a signature by modifying the text of the e-mail message displayed to the user. It was discovered that evolution did not properly validate NTLM authentication challenge packets. A malicious server using NTLM authentication could cause evolution to disclose portions of its memory or crash during user authentication. Multiple integer overflow flaws which could cause heap-based buffer overflows were found in the Base64 encoding routines used by evolution and evolution-data-server. This could cause evolution, or an application using evolution-data-server, to crash, or, possibly, execute an arbitrary code when large untrusted data blocks were Base64-encoded. All users of evolution and evolution-data-server are advised to upgrade to these updated packages, which contain backported patches to correct these issues. All running instances of evolution and evolution-data-server must be restarted for the update to take effect.