diff --git a/src/interfaces/libpq/fe-connect.c b/src/interfaces/libpq/fe-connect.c
index f91f0f2efe..9af830321c 100644
--- a/src/interfaces/libpq/fe-connect.c
+++ b/src/interfaces/libpq/fe-connect.c
@@ -1687,7 +1687,7 @@ useKeepalives(PGconn *conn)
 /*
  * Parse and try to interpret "value" as an integer value, and if successful,
  * store it in *result, complaining if there is any trailing garbage or an
- * overflow.
+ * overflow.  This allows any number of leading and trailing whitespaces.
  */
 static bool
 parse_int_param(const char *value, int *result, PGconn *conn,
@@ -1698,14 +1698,31 @@ parse_int_param(const char *value, int *result, PGconn *conn,
 
 	*result = 0;
 
+	/* strtol(3) skips leading whitespaces */
 	errno = 0;
 	numval = strtol(value, &end, 10);
-	if (errno == 0 && *end == '\0' && numval == (int) numval)
-	{
-		*result = numval;
-		return true;
-	}
 
+	/*
+	 * If no progress was done during the parsing or an error happened, fail.
+	 * This tests properly for overflows of the result.
+	 */
+	if (value == end || errno != 0 || numval != (int) numval)
+		goto error;
+
+	/*
+	 * Skip any trailing whitespace; if anything but whitespace remains before
+	 * the terminating character, fail
+	 */
+	while (*end && *end != '\0' && isspace((unsigned char) *end))
+		end++;
+
+	if (*end && *end != '\0')
+		goto error;
+
+	*result = numval;
+	return true;
+
+error:
 	appendPQExpBuffer(&conn->errorMessage,
 					  libpq_gettext("invalid integer value \"%s\" for connection option \"%s\"\n"),
 					  value, context);
@@ -2008,7 +2025,11 @@ connectDBComplete(PGconn *conn)
 	{
 		if (!parse_int_param(conn->connect_timeout, &timeout, conn,
 							 "connect_timeout"))
+		{
+			/* mark the connection as bad to report the parsing failure */
+			conn->status = CONNECTION_BAD;
 			return 0;
+		}
 
 		if (timeout > 0)
 		{