diff --git a/fs/isofs/export.c b/fs/isofs/export.c
index 8ab83056a9d5..388f20a84f8a 100644
--- a/fs/isofs/export.c
+++ b/fs/isofs/export.c
@@ -24,7 +24,7 @@ isofs_export_iget(struct super_block *sb,
 {
 	struct inode *inode;
 
-	if (block == 0)
+	if (block == 0 || block >= ISOFS_SB(sb)->s_nzones)
 		return ERR_PTR(-ESTALE);
 	inode = isofs_iget(sb, block, offset);
 	if (IS_ERR(inode))