diff --git a/lib/cmdline.c b/lib/cmdline.c
index 171c19b6888e207bd663e9e41a87c7b0fad9a1de..f32d76261cc1b8b189d6bf7253ae63655bbeec4a 100644
--- a/lib/cmdline.c
+++ b/lib/cmdline.c
@@ -233,7 +233,7 @@ char *next_arg(char *args, char **param, char **val)
 				args[i-1] = '\0';
 		}
 	}
-	if (quoted && args[i-1] == '"')
+	if (quoted && i > 0 && args[i-1] == '"')
 		args[i-1] = '\0';
 
 	if (args[i]) {