"It was discovered that the SIEVE component of cyrus-imapd, a highly
scalable enterprise mail system, is vulnerable to a buffer overflow when
processing SIEVE scripts. Due to incorrect use of the sizeof() operator
an attacker is able to pass a negative length to snprintf() calls
resulting in large positive values due to integer conversion. This
causes a buffer overflow which can be used to elevate privileges to the
cyrus system user. An attacker who is able to install SIEVE scripts
executed by the server is therefore able to read and modify arbitrary
email messages on the system.
For the oldstable distribution (etch), this problem has been fixed in
For the stable distribution (lenny), this problem has been fixed in
For the testing (squeeze) and unstable (sid) distribution, this problem
will be fixed soon.
We recommend that you upgrade your cyrus-imapd-2.2 packages."