Description of problem:
The Postfix SMTP server has a memory corruption error when the Cyrus SASL library is used with authentication mechanisms other than PLAIN and LOGIN (the ANONYMOUS mechanism is unaffected but should not be enabled for different reasons). See below for instructions to determine what systems are affected.

Examples of affected Cyrus SASL authentication methods are CRAM-MD5, DIGEST-MD5, EXTERNAL, GSSAPI, KERBEROS_V4, NTLM, OTP, PASSDSS-3DES-1, and SRP.

The error was introduced with the Postfix SASL patch, and is present in all Postfix versions where the command "postconf mail_release_date" reports a value of 20000314 (March 14, 2000) or greater.

This problem was discovered by Thomas Jarosch of Intra2net AG.

The memory corruption is known to result in a program crash (SIGSEV). Remote code execution cannot be excluded. Such code would execute as the unprivileged "postfix" user. This user has no control over processes that run with non-postfix privileges including Postfix processes running as root; the impact may be reduced with configurations that enable the Postfix chroot feature or that use platform-dependent privilege-reducing features.

The problem is fixed in Postfix stable releases 2.5.13, 2.6.10, 2.7.4, 2.8.3; in the Postfix 2.9 development release as of May 1, 2011; patches exist for Postfix version 1.1 and later. All this is available from Postfix mirror sites listed at http://www.postfix.org/download.html. 

Version-Release number of selected component (if applicable):
postfix-2.7.3-1.fc14.i686

How reproducible:
not tested

Additional information:
http://www.postfix.org/CVE-2011-1720.html