diff --git a/applypatch/imgdiff.cpp b/applypatch/imgdiff.cpp
index 3951506..2f0e165 100644
--- a/applypatch/imgdiff.cpp
+++ b/applypatch/imgdiff.cpp
@@ -198,6 +198,7 @@
   if (fread(img, 1, sz, f) != sz) {
     printf("failed to read \"%s\" %s\n", filename, strerror(errno));
     fclose(f);
+    free(img);
     return NULL;
   }
   fclose(f);