diff --git a/lib/std/heap.zig b/lib/std/heap.zig
index ba4abc9ffe39cc1c7231a477cf89dbc57e9fc66d..ccfe3d5055d35eb10f7e519bb277a0ff51e02c3d 100644
--- a/lib/std/heap.zig
+++ b/lib/std/heap.zig
@@ -523,6 +523,9 @@ const WasmPageAllocator = struct {
 
     fn alloc(_: *anyopaque, len: usize, alignment: u29, len_align: u29, ra: usize) error{OutOfMemory}![]u8 {
         _ = ra;
+        if (len > maxInt(usize) - (mem.page_size - 1)) {
+            return error.OutOfMemory;
+        }
         const page_count = nPages(len);
         const page_idx = try allocPages(page_count, alignment);
         return @intToPtr([*]u8, page_idx * mem.page_size)[0..alignPageAllocLen(page_count * mem.page_size, len, len_align)];