diff --git a/NEWS b/NEWS
index 57a141f7bce..252a1978887 100644
--- a/NEWS
+++ b/NEWS
@@ -22,6 +22,7 @@ PHP                                                                        NEWS
   . SA_ONSTACK is now set when signals are disabled. (Kévin Dunglas)
   . Fix GH-9649: Signal handlers now do a no-op instead of crashing when
     executed on threads not managed by TSRM. (Kévin Dunglas)
+  . Fixed potential NULL pointer dereference Windows shm*() functions. (cmb)
 
 - Fileinfo:
   . Upgrade bundled libmagic to 5.43. (Anatol)
diff --git a/TSRM/tsrm_win32.c b/TSRM/tsrm_win32.c
index 22e65173992..f7ecea012b5 100644
--- a/TSRM/tsrm_win32.c
+++ b/TSRM/tsrm_win32.c
@@ -686,7 +686,7 @@ TSRM_API void *shmat(int key, const void *shmaddr, int flags)
 {/*{{{*/
 	shm_pair *shm = shm_get(key, NULL);
 
-	if (!shm->segment) {
+	if (!shm || !shm->segment) {
 		return (void*)-1;
 	}
 
@@ -703,7 +703,7 @@ TSRM_API int shmdt(const void *shmaddr)
 	shm_pair *shm = shm_get(0, (void*)shmaddr);
 	int ret;
 
-	if (!shm->segment) {
+	if (!shm || !shm->segment) {
 		return -1;
 	}
 
@@ -723,7 +723,7 @@ TSRM_API int shmctl(int key, int cmd, struct shmid_ds *buf)
 {/*{{{*/
 	shm_pair *shm = shm_get(key, NULL);
 
-	if (!shm->segment) {
+	if (!shm || !shm->segment) {
 		return -1;
 	}