postfix - several

Several vulnerabilities were discovered in Postfix, a mail transfer
agent. The Common Vulnerabilities and Exposures project identifies
the following problems:

• CVE-2009-2939
  The postinst script grants the postfix user write access to
  /var/spool/postfix/pid, which might allow local users to
  conduct symlink attacks that overwrite arbitrary files.
• CVE-2011-0411
  The STARTTLS implementation does not properly restrict I/O
  buffering, which allows man-in-the-middle attackers to insert
  commands into encrypted SMTP sessions by sending a cleartext
  command that is processed after TLS is in place.
• CVE-2011-1720
  A heap-based read-only buffer overflow allows malicious
  clients to crash the smtpd server process using a crafted SASL
  authentication request.

For the oldstable distribution (lenny), this problem has been fixed in
version 2.5.5-1.1+lenny1.

For the stable distribution (squeeze), this problem has been fixed in
version 2.7.1-1+squeeze1.

For the unstable distribution (sid), this problem has been fixed in
version 2.8.0-1.

We recommend that you upgrade your postfix packages.