diff --git a/sys/kern/uipc_ktls.c b/sys/kern/uipc_ktls.c
--- a/sys/kern/uipc_ktls.c
+++ b/sys/kern/uipc_ktls.c
@@ -3072,6 +3072,7 @@
 
 		if ((m->m_epg_flags & EPG_FLAG_ANON) == 0)
 			ktls_finish_nonanon(m, &state);
+		m->m_flags |= M_RDONLY;
 
 		npages += m->m_epg_nrdy;
 
@@ -3110,6 +3111,7 @@
 
 	if ((m->m_epg_flags & EPG_FLAG_ANON) == 0)
 		ktls_finish_nonanon(m, state);
+	m->m_flags |= M_RDONLY;
 
 	so = state->so;
 	free(state, M_KTLS);