diff --git a/sys/kern/uipc_shm.c b/sys/kern/uipc_shm.c
index 2c9cf92fe5a..d1038766fb1 100644
--- a/sys/kern/uipc_shm.c
+++ b/sys/kern/uipc_shm.c
@@ -1948,7 +1948,7 @@ sysctl_posix_shm_list(SYSCTL_HANDLER_ARGS)
 }
 
 SYSCTL_PROC(_kern_ipc, OID_AUTO, posix_shm_list,
-    CTLFLAG_RD | CTLFLAG_MPSAFE | CTLTYPE_OPAQUE,
+    CTLFLAG_RD | CTLFLAG_PRISON | CTLFLAG_MPSAFE | CTLTYPE_OPAQUE,
     NULL, 0, sysctl_posix_shm_list, "",
     "POSIX SHM list");