[An on-line version of this announcement will be available at http://www.postfix.org/announcements/postfix-2.7.3.html]
Postfix legacy releases 2.7.3, 2.6.9, 2.5.12 and 2.4.16 are available. These releases contain a fix for CVE-2011-0411 which allows plaintext command injection with SMTP sessions over TLS. This defect was introduced with Postfix version 2.2.
Note: CVE-2011-0411 is an issue only for the minority of SMTP clients that actually verify server certificates. Without server certificate verification, clients are always vulnerable to man-in-the-middle attacks that allow attackers to inject plaintext commands or responses into SMTP sessions, and more.
For more details see:
http://www.postfix.org/CVE-2011-0411.html
http://www.kb.cert.org/vuls/id/555316.
Postfix 2.8 and 2.9 are not affected.
The following problems were fixed with the Postfix legacy releases:
Fix for CVE-2011-0411: discard buffered plaintext input, after reading the SMTP "STARTTLS" command or response.
Fix to the local delivery agent: look up the "unextended" address in the local aliases database, when that address has a malformed address extension.
Fix to virtual alias expansion: report a tempfail error, instead of silently ignoring recipients that exceed the virtual_alias_expansion_limit or the virtual_alias_recursion_limit.
Fix for Solaris: the Postfix event engine was deaf for SIGHUP and SIGALRM signals after the switch from select() to /dev/poll. Symptoms were delayed "postfix reload" response, and killed processes with watchdog timeout values under 100 seconds.
Fix for HP-UX: the Postfix event engine was deaf for SIGALRM signals. Symptoms were killed processes with watchdog timeout values under 100 seconds.
Fix for BSD-ish mkdir() to prevent maildir directories from inheriting their group ownership from the parent directory.
Fix to the SMTP client: missing support for mail to [ipv6:ipv6addr] address literal destinations.
FreeBSD back-ported closefrom() from FreeBSD 8x to 7x, breaking Postfix builds retroactively.
Historical note:
Wietse Venema discovered the problem two weeks before the Postfix 2.8 release, and silently fixed it pending further investigation. While investigating the problem's scope and impact, Victor Duchovni found that many other TLS applications were also affected. At that point, CERT/CC was asked to coordinate with the problem's resolution.
You can find the updated Postfix source code at the mirrors listed at http://www.postfix.org/.