The elliptic curve cryptography (ECC) subsystem in OpenSSL 1.0.0d and earlier, when the Elliptic Curve Digital Signature Algorithm (ECDSA) is used for the ECDHE_ECDSA cipher suite, does not properly implement curves over binary fields, which makes it easier for context-dependent attackers to determine private keys via a timing attack and a lattice calculation.

ssl/t1_lib.c in OpenSSL 0.9.8h through 0.9.8q and 1.0.0 through 1.0.0c allows remote attackers to cause a denial of service (crash), and possibly obtain sensitive information in applications that use OpenSSL, via a malformed ClientHello handshake message that triggers an out-of-bounds memory access, aka "OCSP stapling vulnerability."