diff --git a/src/backend/libpq/auth-scram.c b/src/backend/libpq/auth-scram.c
index 0267edb29cd..4bac15fc5c1 100644
--- a/src/backend/libpq/auth-scram.c
+++ b/src/backend/libpq/auth-scram.c
@@ -579,7 +579,7 @@ scram_verify_plain_password(const char *username, const char *password,
 	 * Compare the secret's Server Key with the one computed from the
 	 * user-supplied password.
 	 */
-	return memcmp(computed_key, server_key, key_length) == 0;
+	return timingsafe_bcmp(computed_key, server_key, key_length) == 0;
 }
 
 
@@ -1130,9 +1130,9 @@ verify_final_nonce(scram_state *state)
 
 	if (final_nonce_len != client_nonce_len + server_nonce_len)
 		return false;
-	if (memcmp(state->client_final_nonce, state->client_nonce, client_nonce_len) != 0)
+	if (timingsafe_bcmp(state->client_final_nonce, state->client_nonce, client_nonce_len) != 0)
 		return false;
-	if (memcmp(state->client_final_nonce + client_nonce_len, state->server_nonce, server_nonce_len) != 0)
+	if (timingsafe_bcmp(state->client_final_nonce + client_nonce_len, state->server_nonce, server_nonce_len) != 0)
 		return false;
 
 	return true;
@@ -1186,7 +1186,7 @@ verify_client_proof(scram_state *state)
 				client_StoredKey, &errstr) < 0)
 		elog(ERROR, "could not hash stored key: %s", errstr);
 
-	if (memcmp(client_StoredKey, state->StoredKey, state->key_length) != 0)
+	if (timingsafe_bcmp(client_StoredKey, state->StoredKey, state->key_length) != 0)
 		return false;
 
 	return true;
diff --git a/src/backend/libpq/crypt.c b/src/backend/libpq/crypt.c
index 37ccec355c7..739a2e6fa8b 100644
--- a/src/backend/libpq/crypt.c
+++ b/src/backend/libpq/crypt.c
@@ -293,7 +293,8 @@ md5_crypt_verify(const char *role, const char *shadow_pass,
 		return STATUS_ERROR;
 	}
 
-	if (strcmp(client_pass, crypt_pwd) == 0)
+	if (strlen(client_pass) == strlen(crypt_pwd) &&
+		timingsafe_bcmp(client_pass, crypt_pwd, strlen(crypt_pwd)) == 0)
 	{
 		retval = STATUS_OK;
 
@@ -372,7 +373,8 @@ plain_crypt_verify(const char *role, const char *shadow_pass,
 				*logdetail = errstr;
 				return STATUS_ERROR;
 			}
-			if (strcmp(crypt_client_pass, shadow_pass) == 0)
+			if (strlen(crypt_client_pass) == strlen(shadow_pass) &&
+				timingsafe_bcmp(crypt_client_pass, shadow_pass, strlen(shadow_pass)) == 0)
 				return STATUS_OK;
 			else
 			{
diff --git a/src/interfaces/libpq/fe-auth-scram.c b/src/interfaces/libpq/fe-auth-scram.c
index 99103b7e2b6..08c7c666946 100644
--- a/src/interfaces/libpq/fe-auth-scram.c
+++ b/src/interfaces/libpq/fe-auth-scram.c
@@ -631,7 +631,7 @@ read_server_first_message(fe_scram_state *state, char *input)
 
 	/* Verify immediately that the server used our part of the nonce */
 	if (strlen(nonce) < strlen(state->client_nonce) ||
-		memcmp(nonce, state->client_nonce, strlen(state->client_nonce)) != 0)
+		timingsafe_bcmp(nonce, state->client_nonce, strlen(state->client_nonce)) != 0)
 	{
 		libpq_append_conn_error(conn, "invalid SCRAM response (nonce mismatch)");
 		return false;
@@ -896,8 +896,8 @@ verify_server_signature(fe_scram_state *state, bool *match,
 	pg_hmac_free(ctx);
 
 	/* signature processed, so now check after it */
-	if (memcmp(expected_ServerSignature, state->ServerSignature,
-			   state->key_length) != 0)
+	if (timingsafe_bcmp(expected_ServerSignature, state->ServerSignature,
+						state->key_length) != 0)
 		*match = false;
 	else
 		*match = true;