diff --git a/lang/cem/libcc/stdio/getgrent.c b/lang/cem/libcc/stdio/getgrent.c
index cea6baa16..de75c9df7 100644
--- a/lang/cem/libcc/stdio/getgrent.c
+++ b/lang/cem/libcc/stdio/getgrent.c
@@ -64,7 +64,7 @@ static getline ()
 
 static skip_period () 
 {
-        while (*_buf != ':')
+        while (*_buf && *_buf != ':')
 	        _buf++;
         *_buf++ = '\0';
 }
diff --git a/lang/cem/libcc/stdio/getpwent.c b/lang/cem/libcc/stdio/getpwent.c
index 50ecbbe3d..1ab904167 100644
--- a/lang/cem/libcc/stdio/getpwent.c
+++ b/lang/cem/libcc/stdio/getpwent.c
@@ -65,7 +65,7 @@ static getline ()
 
 static skip_period () 
 {
-	while (*_buf != ':')
+	while (*_buf && *_buf != ':')
 		_buf++;
 
 	*_buf++ = '\0';