diff --git a/sys/crypto/openssl/ossl.c b/sys/crypto/openssl/ossl.c
--- a/sys/crypto/openssl/ossl.c
+++ b/sys/crypto/openssl/ossl.c
@@ -301,7 +301,8 @@
 		error = ossl_newsession_cipher(s, csp);
 		break;
 	case CSP_MODE_AEAD:
-		error = ossl_newsession_cipher(s, csp);
+		if (csp->csp_cipher_alg != CRYPTO_CHACHA20_POLY1305)
+			error = ossl_newsession_cipher(s, csp);
 		break;
 	default:
 		__assert_unreachable();