diff --git a/src/openvpn/crypto_openssl.c b/src/openvpn/crypto_openssl.c
index 7688add..f596b8c 100644
--- a/src/openvpn/crypto_openssl.c
+++ b/src/openvpn/crypto_openssl.c
@@ -789,7 +789,8 @@
 #ifdef EVP_CIPH_FLAG_CTS
                    && !(EVP_CIPHER_flags(cipher) & EVP_CIPH_FLAG_CTS)
 #endif
-                   && !(EVP_CIPHER_flags(cipher) & EVP_CIPH_FLAG_AEAD_CIPHER));
+                   && !(EVP_CIPHER_flags(cipher) & EVP_CIPH_FLAG_AEAD_CIPHER)
+                   && !(EVP_CIPHER_flags(cipher) & EVP_CIPH_FLAG_ENC_THEN_MAC));
     EVP_CIPHER_free(cipher);
     return ret;
 }
diff --git a/src/openvpn/openssl_compat.h b/src/openvpn/openssl_compat.h
index e3e7cf8..fb3c9b1 100644
--- a/src/openvpn/openssl_compat.h
+++ b/src/openvpn/openssl_compat.h
@@ -211,4 +211,9 @@
 #endif
 #endif
 
+/* Introduced in OpenSSL 3.6.0 */
+#ifndef EVP_CIPH_FLAG_ENC_THEN_MAC
+#define EVP_CIPH_FLAG_ENC_THEN_MAC 0x10000000
+#endif
+
 #endif /* OPENSSL_COMPAT_H_ */