diff --git a/NEWS b/NEWS
index faae0d71369..295425d6710 100644
--- a/NEWS
+++ b/NEWS
@@ -58,6 +58,9 @@ PHP                                                                        NEWS
   . Fixed bugs GH-15908 and GH-15026 (leak / assertion failure in streams.c).
     (nielsdos)
 
+- TSRM:
+  . Prevent closing of unrelated handles. (cmb)
+
 - Zip:
   . Added ZipArchive::ER_TRUNCATED_ZIP added in libzip 1.11. (Remi)
 
diff --git a/TSRM/tsrm_win32.c b/TSRM/tsrm_win32.c
index 52fbc95bbd4..4b8445542fc 100644
--- a/TSRM/tsrm_win32.c
+++ b/TSRM/tsrm_win32.c
@@ -708,6 +708,7 @@ TSRM_API int shmget(key_t key, size_t size, int flags)
 	if (NULL != shm->descriptor && (shm->descriptor->shm_perm.key != key || size > shm->descriptor->shm_segsz)) {
 		if (NULL != shm->segment) {
 			CloseHandle(shm->segment);
+			shm->segment = INVALID_HANDLE_VALUE;
 		}
 		UnmapViewOfFile(shm->descriptor);
 		shm->descriptor = NULL;