Aborting the process of SASL authentication can lead to a memory leak when the same login processes are reused. An attacker could use this flaw to cause a denial of service due to memory exhaustion.
A flaw was found in dovecot 2.0 up to 2.2.33 and 2.3.0. A abort of SASL authentication results in a memory leak in Dovecot auth client used by login processes. The leak has impact in high performance configuration where same login processes are reused and can cause the process to crash due to memory exhaustion.
Name: The Dovecot Project
Created dovecot tracking bugs for this issue:
Affects: fedora-all [bug 1538717]
This issue can be mitigated on vulnerable systems by limiting the login process to a single request per process, which is also the default value.
A flaw was found in the original upstream fix, this additional fix is needed:
https://github.com/dovecot/core/commit/a9b135760aea6d1790d447d351c56b78889dac22.patch see this post for details: http://seclists.org/oss-sec/2018/q1/119