diff --git a/ng-dev/misc/sync-module-bazel/sync-module-bazel.ts b/ng-dev/misc/sync-module-bazel/sync-module-bazel.ts
index 0eedc9563..ebe6f2611 100644
--- a/ng-dev/misc/sync-module-bazel/sync-module-bazel.ts
+++ b/ng-dev/misc/sync-module-bazel/sync-module-bazel.ts
@@ -139,6 +139,12 @@ async function processNodeToolchainArgs(
     return args;
   }
 
+  const validatedVersion = semver.valid(effectiveVersion);
+  if (!validatedVersion) {
+    throw new Error('Invalid Node.js version: ' + effectiveVersion);
+  }
+  effectiveVersion = validatedVersion;
+
   Log.info(`Resolving Node.js repositories for v${effectiveVersion}...`);
   const repositories = await getNodeJsRepositories(effectiveVersion);
   const lines = repositories.map(({filename, sha, type}) => {