6 security flaws have been fixed in OpenSSL 1.0.0f:
If X509_V_FLAG_POLICY_CHECK is set in OpenSSL 0.9.8,
then a policy check failure can lead to a double-free.
OpenSSL prior to 1.0.0f and 0.9.8s failed to clear the
bytes used as block cipher padding in SSL 3.0 records.
As a result, in each record, up to 15 bytes of
uninitialized memory may be sent, encrypted, to the SSL
peer. This could include sensitive contents of
previously freed memory.
RFC 3779 data can be included in certificates, and if
it is malformed, may trigger an assertion failure.
This could be used in a denial-of-service attack.
Support for handshake restarts for server gated
cryptograpy (SGC) can be used in a denial-of-service
attack.
A malicious TLS client can send an invalid set of GOST
parameters which will cause the server to crash due to
lack of error checking. This could be used in a
denial-of-service attack.