diff --git a/common/flatpak-run.c b/common/flatpak-run.c
index 1307856fa..ce9c7cb75 100644
--- a/common/flatpak-run.c
+++ b/common/flatpak-run.c
@@ -2823,6 +2823,7 @@ setup_seccomp (FlatpakBwrap   *bwrap,
 
     /* Don't allow subnamespace setups: */
     {SCMP_SYS (unshare), EPERM},
+    {SCMP_SYS (setns), EPERM},
     {SCMP_SYS (mount), EPERM},
     {SCMP_SYS (pivot_root), EPERM},
 #if defined(__s390__) || defined(__s390x__) || defined(__CRIS__)