diff --git a/lib/std/Io/Threaded.zig b/lib/std/Io/Threaded.zig
index ebf728f59d72cde208c79ba91334b8f54a216f99..da5adae30bf6d4683ec0ee85a1ef524e2398c52c 100644
--- a/lib/std/Io/Threaded.zig
+++ b/lib/std/Io/Threaded.zig
@@ -13240,7 +13240,7 @@ fn netReceivePosix(
         .iovlen = 1,
         .control = message.control.ptr,
         .controllen = @intCast(message.control.len),
-        .flags = undefined,
+        .flags = 0,
     };
 
     const syscall = try Syscall.start();