diff --git a/lib/wasm/wasm_exec.js b/lib/wasm/wasm_exec.js
index d71af9e97e8ca9..1280125a6cf124 100644
--- a/lib/wasm/wasm_exec.js
+++ b/lib/wasm/wasm_exec.js
@@ -11,75 +11,71 @@
 		return err;
 	};
 
-	if (!globalThis.fs) {
-		let outputBuf = "";
-		globalThis.fs = {
-			constants: { O_WRONLY: -1, O_RDWR: -1, O_CREAT: -1, O_TRUNC: -1, O_APPEND: -1, O_EXCL: -1, O_DIRECTORY: -1 }, // unused
-			writeSync(fd, buf) {
-				outputBuf += decoder.decode(buf);
-				const nl = outputBuf.lastIndexOf("\n");
-				if (nl != -1) {
-					console.log(outputBuf.substring(0, nl));
-					outputBuf = outputBuf.substring(nl + 1);
-				}
-				return buf.length;
-			},
-			write(fd, buf, offset, length, position, callback) {
-				if (offset !== 0 || length !== buf.length || position !== null) {
-					callback(enosys());
-					return;
-				}
-				const n = this.writeSync(fd, buf);
-				callback(null, n);
-			},
-			chmod(path, mode, callback) { callback(enosys()); },
-			chown(path, uid, gid, callback) { callback(enosys()); },
-			close(fd, callback) { callback(enosys()); },
-			fchmod(fd, mode, callback) { callback(enosys()); },
-			fchown(fd, uid, gid, callback) { callback(enosys()); },
-			fstat(fd, callback) { callback(enosys()); },
-			fsync(fd, callback) { callback(null); },
-			ftruncate(fd, length, callback) { callback(enosys()); },
-			lchown(path, uid, gid, callback) { callback(enosys()); },
-			link(path, link, callback) { callback(enosys()); },
-			lstat(path, callback) { callback(enosys()); },
-			mkdir(path, perm, callback) { callback(enosys()); },
-			open(path, flags, mode, callback) { callback(enosys()); },
-			read(fd, buffer, offset, length, position, callback) { callback(enosys()); },
-			readdir(path, callback) { callback(enosys()); },
-			readlink(path, callback) { callback(enosys()); },
-			rename(from, to, callback) { callback(enosys()); },
-			rmdir(path, callback) { callback(enosys()); },
-			stat(path, callback) { callback(enosys()); },
-			symlink(path, link, callback) { callback(enosys()); },
-			truncate(path, length, callback) { callback(enosys()); },
-			unlink(path, callback) { callback(enosys()); },
-			utimes(path, atime, mtime, callback) { callback(enosys()); },
-		};
-	}
+	// Use local variables instead of polluting the global namespace.
+	// These will be captured by closures in the importObject.
+	let outputBuf = "";
+	const fs = globalThis.fs || {
+		constants: { O_WRONLY: -1, O_RDWR: -1, O_CREAT: -1, O_TRUNC: -1, O_APPEND: -1, O_EXCL: -1, O_DIRECTORY: -1 }, // unused
+		writeSync(fd, buf) {
+			outputBuf += decoder.decode(buf);
+			const nl = outputBuf.lastIndexOf("\n");
+			if (nl != -1) {
+				console.log(outputBuf.substring(0, nl));
+				outputBuf = outputBuf.substring(nl + 1);
+			}
+			return buf.length;
+		},
+		write(fd, buf, offset, length, position, callback) {
+			if (offset !== 0 || length !== buf.length || position !== null) {
+				callback(enosys());
+				return;
+			}
+			const n = this.writeSync(fd, buf);
+			callback(null, n);
+		},
+		chmod(path, mode, callback) { callback(enosys()); },
+		chown(path, uid, gid, callback) { callback(enosys()); },
+		close(fd, callback) { callback(enosys()); },
+		fchmod(fd, mode, callback) { callback(enosys()); },
+		fchown(fd, uid, gid, callback) { callback(enosys()); },
+		fstat(fd, callback) { callback(enosys()); },
+		fsync(fd, callback) { callback(null); },
+		ftruncate(fd, length, callback) { callback(enosys()); },
+		lchown(path, uid, gid, callback) { callback(enosys()); },
+		link(path, link, callback) { callback(enosys()); },
+		lstat(path, callback) { callback(enosys()); },
+		mkdir(path, perm, callback) { callback(enosys()); },
+		open(path, flags, mode, callback) { callback(enosys()); },
+		read(fd, buffer, offset, length, position, callback) { callback(enosys()); },
+		readdir(path, callback) { callback(enosys()); },
+		readlink(path, callback) { callback(enosys()); },
+		rename(from, to, callback) { callback(enosys()); },
+		rmdir(path, callback) { callback(enosys()); },
+		stat(path, callback) { callback(enosys()); },
+		symlink(path, link, callback) { callback(enosys()); },
+		truncate(path, length, callback) { callback(enosys()); },
+		unlink(path, callback) { callback(enosys()); },
+		utimes(path, atime, mtime, callback) { callback(enosys()); },
+	};
 
-	if (!globalThis.process) {
-		globalThis.process = {
-			getuid() { return -1; },
-			getgid() { return -1; },
-			geteuid() { return -1; },
-			getegid() { return -1; },
-			getgroups() { throw enosys(); },
-			pid: -1,
-			ppid: -1,
-			umask() { throw enosys(); },
-			cwd() { throw enosys(); },
-			chdir() { throw enosys(); },
-		}
-	}
+	const process = globalThis.process || {
+		getuid() { return -1; },
+		getgid() { return -1; },
+		geteuid() { return -1; },
+		getegid() { return -1; },
+		getgroups() { throw enosys(); },
+		pid: -1,
+		ppid: -1,
+		umask() { throw enosys(); },
+		cwd() { throw enosys(); },
+		chdir() { throw enosys(); },
+	};
 
-	if (!globalThis.path) {
-		globalThis.path = {
-			resolve(...pathSegments) {
-				return pathSegments.join("/");
-			}
+	const path = globalThis.path || {
+		resolve(...pathSegments) {
+			return pathSegments.join("/");
 		}
-	}
+	};
 
 	if (!globalThis.crypto) {
 		throw new Error("globalThis.crypto is not available, polyfill required (crypto.getRandomValues only)");
@@ -221,7 +217,7 @@
 				return this._inst.exports.testExport(a, b);
 			}
 
-			const timeOrigin = Date.now() - performance.now();
+			const timeOrigin = Date.now() - globalThis.performance.now();
 			this.importObject = {
 				_gotest: {
 					add: (a, b) => a + b,
@@ -264,7 +260,7 @@
 					// func nanotime1() int64
 					"runtime.nanotime1": (sp) => {
 						sp >>>= 0;
-						setInt64(sp + 8, (timeOrigin + performance.now()) * 1000000);
+						setInt64(sp + 8, (timeOrigin + globalThis.performance.now()) * 1000000);
 					},
 
 					// func walltime() (sec int64, nsec int32)
@@ -306,7 +302,7 @@
 					// func getRandomData(r []byte)
 					"runtime.getRandomData": (sp) => {
 						sp >>>= 0;
-						crypto.getRandomValues(loadSlice(sp + 8));
+						globalThis.crypto.getRandomValues(loadSlice(sp + 8));
 					},
 
 					// func finalizeRef(v ref)