The MITRE CVE dictionary describes this issue as:
The DTLS retransmission implementation in OpenSSL 1.0.0 before 1.0.0l and 1.0.1 before 1.0.1f does not properly maintain data structures for digest and encryption contexts, which might allow man-in-the-middle attackers to trigger the use of a different context and cause a denial of service (application crash) by interfering with packet delivery, related to ssl/d1_both.c and ssl/t1_enc.c.
Find out more about CVE-2013-6450 from the
MITRE CVE dictionary dictionary and
This issue did not affect the versions of openssl as shipped with Red Hat Enterprise Linux 5 and earlier.