diff --git a/src/wasm/rust/harfbuzz-wasm/src/lib.rs b/src/wasm/rust/harfbuzz-wasm/src/lib.rs
index 3fe1fa545..3be27f614 100644
--- a/src/wasm/rust/harfbuzz-wasm/src/lib.rs
+++ b/src/wasm/rust/harfbuzz-wasm/src/lib.rs
@@ -41,7 +41,7 @@ extern "C" {
     fn font_glyph_to_string(font: u32, glyph: u32, str: *const u8, len: u32);
     fn font_get_glyph_h_advance(font: u32, glyph: u32) -> i32;
     fn font_get_glyph_v_advance(font: u32, glyph: u32) -> i32;
-    fn face_copy_table(font: u32, tag: u32) -> Blob;
+    fn face_copy_table(font: u32, tag: u32, blob: *mut Blob) -> bool;
     fn buffer_copy_contents(buffer: u32, cbuffer: *mut CBufferContents) -> bool;
     fn buffer_set_contents(buffer: u32, cbuffer: &CBufferContents) -> bool;
     fn debugprint(s: *const u8);
@@ -165,7 +165,14 @@ impl Face {
         tag_u |= (chars.next().unwrap() as u32) << 16;
         tag_u |= (chars.next().unwrap() as u32) << 8;
         tag_u |= chars.next().unwrap() as u32;
-        unsafe { face_copy_table(self.0, tag_u) }
+        let mut blob = Blob {
+            data: std::ptr::null_mut(),
+            length: 0,
+        };
+        unsafe {
+            face_copy_table(self.0, tag_u, &mut blob);
+        }
+        blob
     }
 
     /// Get the face's design units per em.