diff --git a/dist/index.js b/dist/index.js
index 0f15b44..809fe89 100644
--- a/dist/index.js
+++ b/dist/index.js
@@ -11515,7 +11515,7 @@ function getManifestDir(args) {
 function parseRustToolchain(content) {
     const toml = (0, toml_1.parse)(content.toString());
     const toolchain = toml === null || toml === void 0 ? void 0 : toml.toolchain;
-    return toolchain === null || toolchain === void 0 ? void 0 : toolchain.channel;
+    return (toolchain === null || toolchain === void 0 ? void 0 : toolchain.channel) || '';
 }
 async function getRustToolchain(args) {
     let rustToolchain = core.getInput('rust-toolchain');
@@ -11940,7 +11940,7 @@ function setupSccacheEnv() {
 async function hostBuild(maturinRelease, args) {
     const command = core.getInput('command');
     const target = getRustTarget(args);
-    const rustToolchain = await getRustToolchain(args);
+    const rustToolchain = (await getRustToolchain(args)) || 'stable';
     const rustupComponents = core.getInput('rustup-components');
     const workdir = getWorkingDirectory();
     const sccache = core.getBooleanInput('sccache');
diff --git a/src/index.ts b/src/index.ts
index fc1a2ea..db2526a 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -197,7 +197,7 @@ function getManifestDir(args: string[]): string {
 function parseRustToolchain(content: string): string {
   const toml = parseTOML(content.toString())
   const toolchain = toml?.toolchain as JsonMap
-  return toolchain?.channel as string
+  return (toolchain?.channel as string) || ''
 }
 
 async function getRustToolchain(args: string[]): Promise<string> {
@@ -759,7 +759,7 @@ async function hostBuild(
 ): Promise<number> {
   const command = core.getInput('command')
   const target = getRustTarget(args)
-  const rustToolchain = await getRustToolchain(args)
+  const rustToolchain = (await getRustToolchain(args)) || 'stable'
   const rustupComponents = core.getInput('rustup-components')
   const workdir = getWorkingDirectory()
   const sccache = core.getBooleanInput('sccache')