diff --git a/protocol/virtual-keyboard-unstable-v1.xml b/protocol/virtual-keyboard-unstable-v1.xml
index d9c8464ca..a888e5f87 100644
--- a/protocol/virtual-keyboard-unstable-v1.xml
+++ b/protocol/virtual-keyboard-unstable-v1.xml
@@ -47,6 +47,7 @@
 
     <enum name="error">
       <entry name="no_keymap" value="0" summary="No keymap was set"/>
+      <entry name="invalid_keymap_format" value="1" summary="Invalid keymap format"/>
     </enum>
 
     <request name="key">
diff --git a/types/wlr_virtual_keyboard_v1.c b/types/wlr_virtual_keyboard_v1.c
index 465b97dd3..03838cff3 100644
--- a/types/wlr_virtual_keyboard_v1.c
+++ b/types/wlr_virtual_keyboard_v1.c
@@ -44,6 +44,13 @@ static void virtual_keyboard_keymap(struct wl_client *client,
 		return;
 	}
 
+	if (!wl_keyboard_keymap_format_is_valid(format, 1)) {
+		wl_resource_post_error(resource,
+			ZWP_VIRTUAL_KEYBOARD_V1_ERROR_INVALID_KEYMAP_FORMAT,
+			"Invalid keymap format");
+		return;
+	}
+
 	struct xkb_context *context = xkb_context_new(XKB_CONTEXT_NO_FLAGS);
 	if (!context) {
 		goto context_fail;