diff --git a/src/modules/ecdsa_adaptor/tests_impl.h b/src/modules/ecdsa_adaptor/tests_impl.h
index 0c849d5d2..ebafbcedc 100644
--- a/src/modules/ecdsa_adaptor/tests_impl.h
+++ b/src/modules/ecdsa_adaptor/tests_impl.h
@@ -1032,7 +1032,7 @@ void adaptor_tests(void) {
     CHECK(secp256k1_ecdsa_adaptor_verify(ctx, adaptor_sig, &enckey, msg, &enckey) == 0);
     CHECK(secp256k1_ecdsa_adaptor_verify(ctx, adaptor_sig, &pubkey, msg, &pubkey) == 0);
     {
-        unsigned char adaptor_sig_tmp[65];
+        unsigned char adaptor_sig_tmp[162];
         memcpy(adaptor_sig_tmp, adaptor_sig, sizeof(adaptor_sig_tmp));
         rand_flip_bit(&adaptor_sig_tmp[1], sizeof(adaptor_sig_tmp) - 1);
         CHECK(secp256k1_ecdsa_adaptor_verify(ctx, adaptor_sig_tmp, &pubkey, msg, &enckey) == 0);