diff --git a/TSRM/tsrm_win32.c b/TSRM/tsrm_win32.c
index 39fb75c33dd..52fbc95bbd4 100644
--- a/TSRM/tsrm_win32.c
+++ b/TSRM/tsrm_win32.c
@@ -710,6 +710,7 @@ TSRM_API int shmget(key_t key, size_t size, int flags)
 			CloseHandle(shm->segment);
 		}
 		UnmapViewOfFile(shm->descriptor);
+		shm->descriptor = NULL;
 		return -1;
 	}
 
@@ -745,8 +746,8 @@ TSRM_API int shmdt(const void *shmaddr)
 	shm->descriptor->shm_lpid  = getpid();
 	shm->descriptor->shm_nattch--;
 
-	ret = 1;
-	if (!ret  && shm->descriptor->shm_nattch <= 0) {
+	ret = 0;
+	if (shm->descriptor->shm_nattch <= 0) {
 		ret = UnmapViewOfFile(shm->descriptor) ? 0 : -1;
 		shm->descriptor = NULL;
 	}
diff --git a/ext/shmop/tests/gh14537.phpt b/ext/shmop/tests/gh14537.phpt
new file mode 100644
index 00000000000..05af26a70ff
--- /dev/null
+++ b/ext/shmop/tests/gh14537.phpt
@@ -0,0 +1,27 @@
+--TEST--
+GH-14537: shmop Windows 11 crashes the process
+--EXTENSIONS--
+shmop
+--SKIPIF--
+<?php
+if (PHP_OS_FAMILY !== 'Windows') die('skip only for Windows');
+?>
+--FILE--
+<?php
+$str = 'Hello World';
+
+$shm_key = ftok(__FILE__, 'p');
+
+$shm_id1 = shmop_open($shm_key, 'c', 0644, strlen($str));
+shmop_delete($shm_id1);
+var_dump($shm_id1);
+
+$shm_id2 = shmop_open($shm_key, 'c', 0644, strlen($str) + 10);
+var_dump($shm_id2);
+?>
+--EXPECTF--
+object(Shmop)#1 (0) {
+}
+
+Warning: shmop_open(): Unable to attach or create shared memory segment "No error" in %s on line %d
+bool(false)