diff --git a/js/src/shell/fuzz-flags.txt b/js/src/shell/fuzz-flags.txt
index 5dc1b565ff7d..35e57967c70e 100644
--- a/js/src/shell/fuzz-flags.txt
+++ b/js/src/shell/fuzz-flags.txt
@@ -75,6 +75,7 @@
 --wasm-compiler=baseline+optimizing
 --test-wasm-await-tier2
 --wasm-disable-huge-memory
+--setpref=wasm_js_string_builtins=true
 
 # CPU instruction set-related
 --no-sse3