diff --git a/OpenSSL/SSL.py b/OpenSSL/SSL.py
index a35c299..d2b001a 100644
--- a/OpenSSL/SSL.py
+++ b/OpenSSL/SSL.py
@@ -45,7 +45,10 @@
 OP_NO_TLSv1_1 = getattr(_lib, "SSL_OP_NO_TLSv1_1", 0)
 OP_NO_TLSv1_2 = getattr(_lib, "SSL_OP_NO_TLSv1_2", 0)
 
-MODE_RELEASE_BUFFERS = _lib.SSL_MODE_RELEASE_BUFFERS
+try:
+    MODE_RELEASE_BUFFERS = _lib.SSL_MODE_RELEASE_BUFFERS
+except AttributeError:
+    pass
 
 OP_SINGLE_DH_USE = _lib.SSL_OP_SINGLE_DH_USE
 OP_EPHEMERAL_RSA = _lib.SSL_OP_EPHEMERAL_RSA
@@ -54,7 +57,10 @@
 OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG = _lib.SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG
 OP_SSLREF2_REUSE_CERT_TYPE_BUG = _lib.SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG
 OP_MICROSOFT_BIG_SSLV3_BUFFER = _lib.SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER
-OP_MSIE_SSLV2_RSA_PADDING = getattr(_lib, "SSL_OP_MSIE_SSLV2_RSA_PADDING", 0)
+try:
+    OP_MSIE_SSLV2_RSA_PADDING = _lib.SSL_OP_MSIE_SSLV2_RSA_PADDING
+except AttributeError:
+    pass
 OP_SSLEAY_080_CLIENT_DH_BUG = _lib.SSL_OP_SSLEAY_080_CLIENT_DH_BUG
 OP_TLS_D5_BUG = _lib.SSL_OP_TLS_D5_BUG
 OP_TLS_BLOCK_PADDING_BUG = _lib.SSL_OP_TLS_BLOCK_PADDING_BUG