diff --git a/packages/cli/cli/src/rerunFernCliAtVersion.ts b/packages/cli/cli/src/rerunFernCliAtVersion.ts
index d5de632c9ec..80f77fdb4e0 100644
--- a/packages/cli/cli/src/rerunFernCliAtVersion.ts
+++ b/packages/cli/cli/src/rerunFernCliAtVersion.ts
@@ -35,7 +35,7 @@ export async function rerunFernCliAtVersion({
             [FERN_CWD_ENV_VAR]: process.env[FERN_CWD_ENV_VAR] ?? process.cwd()
         }
     });
-    if (stdout.includes("code EEXIST") || stderr.includes("code EEXIST")) {
+    if (stdout?.includes("code EEXIST") || stderr?.includes("code EEXIST")) {
         // try again if there is a npx conflict
         return await rerunFernCliAtVersion({
             version,
diff --git a/packages/cli/cli/versions.yml b/packages/cli/cli/versions.yml
index b0ca6772879..7c80c0c0805 100644
--- a/packages/cli/cli/versions.yml
+++ b/packages/cli/cli/versions.yml
@@ -1,3 +1,11 @@
+- changelogEntry:
+    - summary: |
+        Make sure to check for optionality when parsing stdout and stderr in CLI. This 
+        removes the error: `Cannot read properties of undefined (reading 'includes')`. 
+      type: fix
+  irVersion: 53
+  version: 0.42.1
+
 - changelogEntry:
     - summary: |
         If you merge multiple OpenAPI specs with namespaces, `fern check` will no longer