diff --git a/lib/libc/stdio/fclose.c b/lib/libc/stdio/fclose.c
index 56bd0ac4a..85ecb420a 100644
--- a/lib/libc/stdio/fclose.c
+++ b/lib/libc/stdio/fclose.c
@@ -25,6 +25,7 @@ fclose(FILE *fp)
 	if (_close(fileno(fp))) retval = EOF;
 	if ( io_testflag(fp,_IOMYBUF) && fp->_buf )
 		free((void *)fp->_buf);
+	fp->_buf = NULL;
 	if (fp != stdin && fp != stdout && fp != stderr)
 		free((void *)fp);
 	return retval;