diff --git a/sys/kern/imgact_elf.c b/sys/kern/imgact_elf.c
--- a/sys/kern/imgact_elf.c
+++ b/sys/kern/imgact_elf.c
@@ -190,6 +190,11 @@
     CTLFLAG_RWTUN, &__elfN(sigfastblock), 0,
     "enable sigfastblock for new processes");
 
+static bool __elfN(allow_wx) = true;
+SYSCTL_BOOL(__CONCAT(_kern_elf, __ELF_WORD_SIZE), OID_AUTO, allow_wx,
+    CTLFLAG_RWTUN, &__elfN(allow_wx), 0,
+    "Allow pages to be mapped simultaneously writable and executable");
+
 static Elf_Brandinfo *elf_brand_list[MAX_BRANDS];
 
 #define	aligned(a, t)	(rounddown2((u_long)(a), sizeof(t)) == (u_long)(a))
@@ -1237,6 +1242,9 @@
 			imgp->map_flags |= MAP_ASLR_IGNSTART;
 	}
 
+	if (!__elfN(allow_wx) && (fctl0 & NT_FREEBSD_FCTL_WXNEEDED) == 0)
+		imgp->map_flags |= MAP_WXORX;
+
 	error = exec_new_vmspace(imgp, sv);
 	vmspace = imgp->proc->p_vmspace;
 	map = &vmspace->vm_map;
diff --git a/sys/kern/kern_exec.c b/sys/kern/kern_exec.c
--- a/sys/kern/kern_exec.c
+++ b/sys/kern/kern_exec.c
@@ -1043,6 +1043,7 @@
 	struct rlimit rlim_stack;
 	vm_offset_t sv_minuser, stack_addr;
 	vm_map_t map;
+	vm_prot_t stack_prot;
 	u_long ssiz;
 
 	imgp->vmspace_destroyed = 1;
@@ -1074,12 +1075,12 @@
 		pmap_remove_pages(vmspace_pmap(vmspace));
 		vm_map_remove(map, vm_map_min(map), vm_map_max(map));
 		/*
-		 * An exec terminates mlockall(MCL_FUTURE), ASLR state
-		 * must be re-evaluated.
+		 * An exec terminates mlockall(MCL_FUTURE).
+		 * ASLR and W^X states must be re-evaluated.
 		 */
 		vm_map_lock(map);
 		vm_map_modflags(map, 0, MAP_WIREFUTURE | MAP_ASLR |
-		    MAP_ASLR_IGNSTART);
+		    MAP_ASLR_IGNSTART | MAP_WXORX);
 		vm_map_unlock(map);
 	} else {
 		error = vmspace_exec(p, sv_minuser, sv->sv_maxuser);
@@ -1126,11 +1127,16 @@
 	if (ssiz < imgp->eff_stack_sz)
 		imgp->eff_stack_sz = ssiz;
 	stack_addr = sv->sv_usrstack - ssiz;
-	error = vm_map_stack(map, stack_addr, (vm_size_t)ssiz,
-	    obj != NULL && imgp->stack_prot != 0 ? imgp->stack_prot :
-	    sv->sv_stackprot, VM_PROT_ALL, MAP_STACK_GROWS_DOWN);
-	if (error != KERN_SUCCESS)
+	stack_prot = obj != NULL && imgp->stack_prot != 0 ?
+	    imgp->stack_prot :sv->sv_stackprot;
+	error = vm_map_stack(map, stack_addr, (vm_size_t)ssiz, stack_prot,
+	    VM_PROT_ALL, MAP_STACK_GROWS_DOWN);
+	if (error != KERN_SUCCESS) {
+		uprintf("exec_new_vmspace: mapping stack size %#jx prot %#x "
+		    "failed mach error %d errno %d\n", (uintmax_t)ssiz,
+		    stack_prot, error, vm_mmap_to_errno(error));
 		return (vm_mmap_to_errno(error));
+	}
 
 	/*
 	 * vm_ssize and vm_maxsaddr are somewhat antiquated concepts, but they
diff --git a/sys/vm/vm_map.h b/sys/vm/vm_map.h
--- a/sys/vm/vm_map.h
+++ b/sys/vm/vm_map.h
@@ -228,6 +228,7 @@
 #define	MAP_ASLR		0x08	/* enabled ASLR */
 #define	MAP_ASLR_IGNSTART	0x10
 #define	MAP_REPLENISH		0x20
+#define	MAP_WXORX		0x40	/* enforce W^X */
 
 #ifdef	_KERNEL
 #if defined(KLD_MODULE) && !defined(KLD_TIED)
diff --git a/sys/vm/vm_map.c b/sys/vm/vm_map.c
--- a/sys/vm/vm_map.c
+++ b/sys/vm/vm_map.c
@@ -1671,6 +1671,10 @@
 	if (start == end || !vm_map_range_valid(map, start, end))
 		return (KERN_INVALID_ADDRESS);
 
+	if ((map->flags & MAP_WXORX) != 0 && (prot & (VM_PROT_WRITE |
+	    VM_PROT_EXECUTE)) == (VM_PROT_WRITE | VM_PROT_EXECUTE))
+		return (KERN_PROTECTION_FAILURE);
+
 	/*
 	 * Find the entry prior to the proposed starting address; if it's part
 	 * of an existing entry, this range is bogus.
@@ -2751,6 +2755,13 @@
 	in_tran = NULL;
 	vm_map_lock(map);
 
+	if ((map->flags & MAP_WXORX) != 0 && (new_prot &
+	    (VM_PROT_WRITE | VM_PROT_EXECUTE)) == (VM_PROT_WRITE |
+	    VM_PROT_EXECUTE)) {
+		vm_map_unlock(map);
+		return (KERN_PROTECTION_FAILURE);
+	}
+
 	/*
 	 * Ensure that we are not concurrently wiring pages.  vm_map_wire() may
 	 * need to fault pages into the map and will drop the map lock while