diff --git a/stdio-common/vfscanf.c b/stdio-common/vfscanf.c
index b0fc8f00e0..d63fd364a5 100644
--- a/stdio-common/vfscanf.c
+++ b/stdio-common/vfscanf.c
@@ -308,7 +308,7 @@ __vfscanf (FILE *s, const char *format, va_list argptr)
   char *str = NULL;
   wchar_t *wstr = NULL;
   char **strptr = NULL;
-  size_t strsize = 0;
+  ssize_t strsize = 0;
   /* We must not react on white spaces immediately because they can
      possibly be matched even if in the input stream no character is
      available anymore.  */