diff --git a/src/libImaging/Convert.c b/src/libImaging/Convert.c
index 48259dcdc..8f580c294 100644
--- a/src/libImaging/Convert.c
+++ b/src/libImaging/Convert.c
@@ -1794,4 +1794,5 @@ ImagingConvertInit(void) {
 void
 ImagingConvertFree(void) {
     free(converters);
+    converters = NULL;
 }
diff --git a/src/libImaging/Pack.c b/src/libImaging/Pack.c
index da714dacc..aaa074c92 100644
--- a/src/libImaging/Pack.c
+++ b/src/libImaging/Pack.c
@@ -815,4 +815,5 @@ ImagingPackInit(void) {
 void
 ImagingPackFree(void) {
     free(packers);
+    packers = NULL;
 }