diff --git a/mettle/src/stdapi/fs/file.c b/mettle/src/stdapi/fs/file.c
index bfe45d66..dfbf3fd4 100644
--- a/mettle/src/stdapi/fs/file.c
+++ b/mettle/src/stdapi/fs/file.c
@@ -560,8 +560,9 @@ fs_mkdir(struct tlv_handler_ctx *ctx)
 		return tlv_packet_response_result(ctx, TLV_RESULT_ENOMEM);
 	}
 
-	// take into account null byte at the end of path and the one we add in sprintf
-	base_dir = malloc(strlen(path_dup)+2);
+	// take into account null byte at the end of path and the one we add in snprintf
+	size_t base_max_len = strlen(path_dup) + 2;
+	base_dir = malloc(base_max_len);
 	
 	if(base_dir == NULL)
 	{
@@ -569,7 +570,7 @@ fs_mkdir(struct tlv_handler_ctx *ctx)
 		return tlv_packet_response_result(ctx, TLV_RESULT_ENOMEM);
 	}
 
-	tmp = malloc(strlen(path_dup)+2);
+	tmp = malloc(base_max_len);
 	
 	if(tmp == NULL)
 	{
@@ -579,15 +580,22 @@ fs_mkdir(struct tlv_handler_ctx *ctx)
 	}
 
 	dir = strtok(path_dup, "/");
+
+	if(dir == NULL) {
+		free(tmp);
+		free(path_dup);
+		free(base_dir);
+		return tlv_packet_response_result(ctx, TLV_RESULT_EINVAL);
+	}
 	
 	//address absolute paths — check original path since strtok modifies path_dup
 	if (path[0] == '/')
 	{
-		sprintf(base_dir, "/%s/", dir);
+		snprintf(base_dir, base_max_len, "/%s/", dir);
 	}
 	else
 	{	
-		sprintf(base_dir, "%s/", dir);
+		snprintf(base_dir, base_max_len, "%s/", dir);
 	}
 
 	while(dir != NULL)
@@ -614,7 +622,7 @@ fs_mkdir(struct tlv_handler_ctx *ctx)
 		dir = strtok(NULL, "/");
 		if(dir != NULL)
 		{
-			sprintf(tmp, "%s%s/", base_dir, dir);
+			snprintf(tmp, base_max_len, "%s%s/", base_dir, dir);
 			strcpy(base_dir, tmp);
 		}
 	}
diff --git a/mettle/src/stdapi/ui/osx_desktop.m b/mettle/src/stdapi/ui/osx_desktop.m
index 094a19bb..5e4fe537 100644
--- a/mettle/src/stdapi/ui/osx_desktop.m
+++ b/mettle/src/stdapi/ui/osx_desktop.m
@@ -8,6 +8,15 @@
   struct tlv_packet *p;
   uint32_t quality = 0;
   tlv_packet_get_u32(ctx->req, TLV_TYPE_DESKTOP_SCREENSHOT_QUALITY, &quality);
+
+#if __MAC_OS_X_VERSION_MAX_ALLOWED >= 140000
+  if (@available(macOS 14.4, *)) {
+    // ScreenCaptureKit is required on macOS 14.4+ but is not yet implemented.
+    return tlv_packet_response_result(ctx, TLV_RESULT_FAILURE);
+  }
+#endif
+
+#if __MAC_OS_X_VERSION_MAX_ALLOWED < 150000
   @autoreleasepool {
     CGImageRef image = CGDisplayCreateImage(kCGDirectMainDisplay);
     CFMutableDataRef newImageData = CFDataCreateMutable(NULL, 0);
@@ -26,4 +35,7 @@
     }
   }
   return p;
+#else
+  return tlv_packet_response_result(ctx, TLV_RESULT_FAILURE);
+#endif
 }