diff --git a/packages/cli/src/pty-manager.ts b/packages/cli/src/pty-manager.ts
index 1f49aab..6c60931 100644
--- a/packages/cli/src/pty-manager.ts
+++ b/packages/cli/src/pty-manager.ts
@@ -20,12 +20,11 @@ export function getDefaultShell(): string {
  * Inherits the current process env and sets TERM for proper terminal behavior.
  */
 function buildEnv(): Record<string, string> {
-  const env: Record<string, string> = {};
-  for (const [key, value] of Object.entries(process.env)) {
-    if (value !== undefined) {
-      env[key] = value;
-    }
-  }
+  const env = Object.fromEntries(
+    Object.entries(process.env).filter(
+      (entry): entry is [string, string] => entry[1] !== undefined
+    )
+  );
   // Set TERM for unix systems to enable color and cursor support
   if (process.platform !== "win32") {
     env["TERM"] = env["TERM"] || "xterm-256color";
diff --git a/packages/hub/src/windows-firewall.ts b/packages/hub/src/windows-firewall.ts
index fe77809..654f4bb 100644
--- a/packages/hub/src/windows-firewall.ts
+++ b/packages/hub/src/windows-firewall.ts
@@ -32,7 +32,9 @@ export class WindowsFirewall {
   async addRule(label: string, port: number): Promise<{ success: boolean; error?: string }> {
     if (!this.isWindows) return { success: true };
 
-    const ruleName = `${RULE_PREFIX}-${label}`;
+    // Sanitize label to prevent log/command injection
+    const safeLabel = label.replace(/[^a-zA-Z0-9._-]/g, "_").slice(0, 64);
+    const ruleName = `${RULE_PREFIX}-${safeLabel}`;
 
     // Skip if already tracked
     if (this.rules.has(ruleName)) return { success: true };
@@ -70,7 +72,8 @@ export class WindowsFirewall {
   async removeRule(label: string): Promise<void> {
     if (!this.isWindows) return;
 
-    const ruleName = `${RULE_PREFIX}-${label}`;
+    const safeLabel = label.replace(/[^a-zA-Z0-9._-]/g, "_").slice(0, 64);
+    const ruleName = `${RULE_PREFIX}-${safeLabel}`;
     await this.runNetsh([
       "advfirewall", "firewall", "delete", "rule",
       `name=${ruleName}`,
diff --git a/scripts/sync-versions.mjs b/scripts/sync-versions.mjs
index 0fe67d2..1a03e9e 100644
--- a/scripts/sync-versions.mjs
+++ b/scripts/sync-versions.mjs
@@ -16,6 +16,13 @@ if (!version) {
   process.exit(1);
 }
 
+// Validate semver format to prevent injection via crafted version strings
+const SEMVER_RE = /^\d+\.\d+\.\d+(-[\w.]+)?(\+[\w.]+)?$/;
+if (!SEMVER_RE.test(version)) {
+  console.error(`Invalid version format: "${version}". Expected semver (e.g. 1.2.3).`);
+  process.exit(1);
+}
+
 const packagesDir = join(import.meta.dirname, "..", "packages");
 const packages = readdirSync(packagesDir, { withFileTypes: true })
   .filter((d) => d.isDirectory())