diff --git a/.changeset/patch-secure-install-assets.md b/.changeset/patch-secure-install-assets.md
new file mode 100644
index 0000000000..910b905d12
--- /dev/null
+++ b/.changeset/patch-secure-install-assets.md
@@ -0,0 +1,5 @@
+---
+"gh-aw": patch
+---
+
+Harden the Copilot CLI installer to download release binaries directly and verify SHA256 checksums before running, and avoid shell-interpreted `exec.exec` calls in `upload_assets.cjs` by using the array argument form.
diff --git a/actions/setup/js/upload_assets.cjs b/actions/setup/js/upload_assets.cjs
index f116c773da..e3f4936306 100644
--- a/actions/setup/js/upload_assets.cjs
+++ b/actions/setup/js/upload_assets.cjs
@@ -95,8 +95,8 @@ async function main() {
   try {
     // Check if orphaned branch already exists, if not create it
     try {
-      await exec.exec(`git rev-parse --verify origin/${normalizedBranchName}`);
-      await exec.exec(`git checkout -B ${normalizedBranchName} origin/${normalizedBranchName}`);
+      await exec.exec("git", ["rev-parse", "--verify", `origin/${normalizedBranchName}`]);
+      await exec.exec("git", ["checkout", "-B", normalizedBranchName, `origin/${normalizedBranchName}`]);
       core.info(`Checked out existing branch from origin: ${normalizedBranchName}`);
     } catch (originError) {
       // Validate that branch starts with "assets/" prefix before creating orphaned branch
@@ -111,9 +111,9 @@ async function main() {
 
       // Branch doesn't exist on origin and has valid prefix, create orphaned branch
       core.info(`Creating new orphaned branch: ${normalizedBranchName}`);
-      await exec.exec(`git checkout --orphan ${normalizedBranchName}`);
-      await exec.exec(`git rm -rf .`);
-      await exec.exec(`git clean -fdx`);
+      await exec.exec("git", ["checkout", "--orphan", normalizedBranchName]);
+      await exec.exec("git", ["rm", "-rf", "."]);
+      await exec.exec("git", ["clean", "-fdx"]);
     }
 
     // Process each asset
@@ -171,7 +171,7 @@ async function main() {
       if (isStaged) {
         core.summary.addRaw("## 🎭 Staged Mode: Asset Publication Preview");
       } else {
-        await exec.exec(`git push origin ${normalizedBranchName}`);
+        await exec.exec("git", ["push", "origin", normalizedBranchName]);
         core.summary.addRaw("## Assets").addRaw(`Successfully uploaded **${uploadCount}** assets to branch \`${normalizedBranchName}\``).addRaw("");
         core.info(`Successfully uploaded ${uploadCount} assets to branch ${normalizedBranchName}`);
       }
diff --git a/actions/setup/sh/install_copilot_cli.sh b/actions/setup/sh/install_copilot_cli.sh
index e21de647f5..3a508e19ea 100755
--- a/actions/setup/sh/install_copilot_cli.sh
+++ b/actions/setup/sh/install_copilot_cli.sh
@@ -1,26 +1,25 @@
 #!/usr/bin/env bash
-# Install GitHub Copilot CLI with retry logic
+# Install GitHub Copilot CLI with SHA256 checksum verification
 # Usage: install_copilot_cli.sh [VERSION]
 #
-# This script downloads and installs the GitHub Copilot CLI from the official
-# installer script with retry logic to handle transient network failures.
+# This script downloads and installs the GitHub Copilot CLI directly from GitHub
+# releases with SHA256 checksum verification, following the secure pattern from
+# install_awf_binary.sh to avoid executing unverified downloaded scripts.
 #
 # Arguments:
-#   VERSION - Optional Copilot CLI version to install (default: latest from installer)
+#   VERSION - Optional Copilot CLI version to install (default: latest release)
 #
-# Features:
-#   - Retries download up to 3 times with exponential backoff
-#   - Verifies installation after completion
-#   - Downloads to temp file for security
-#   - Cleans up temp files after installation
+# Security features:
+#   - Downloads binary directly from GitHub releases (no installer script execution)
+#   - Verifies SHA256 checksum against official SHA256SUMS.txt
+#   - Fails fast if checksum verification fails
 
 set -euo pipefail
 
 # Configuration
 VERSION="${1:-}"
-INSTALLER_URL="https://raw.githubusercontent.com/github/copilot-cli/main/install.sh"
-INSTALLER_TEMP="/tmp/copilot-install.sh"
-MAX_ATTEMPTS=3
+COPILOT_REPO="github/copilot-cli"
+INSTALL_DIR="/usr/local/bin"
 COPILOT_DIR="/home/runner/.copilot"
 
 # Fix directory ownership before installation
@@ -32,52 +31,93 @@ echo "Ensuring correct ownership of $COPILOT_DIR..."
 mkdir -p "$COPILOT_DIR"
 sudo chown -R runner:runner "$COPILOT_DIR"
 
-# Function to download installer with retry logic
-download_installer_with_retry() {
-  local attempt=1
-  local wait_time=5
-  
-  while [ $attempt -le $MAX_ATTEMPTS ]; do
-    echo "Attempt $attempt of $MAX_ATTEMPTS: Downloading Copilot CLI installer..."
-    
-    if curl -fsSL "$INSTALLER_URL" -o "$INSTALLER_TEMP" 2>&1; then
-      echo "Successfully downloaded installer"
-      return 0
-    fi
-    
-    if [ $attempt -lt $MAX_ATTEMPTS ]; then
-      echo "Failed to download installer. Retrying in ${wait_time}s..."
-      sleep $wait_time
-      wait_time=$((wait_time * 2))  # Exponential backoff
-    else
-      echo "ERROR: Failed to download installer after $MAX_ATTEMPTS attempts"
-      return 1
-    fi
-    attempt=$((attempt + 1))
-  done
+# Detect OS and architecture
+OS="$(uname -s)"
+ARCH="$(uname -m)"
+
+# Map architecture to Copilot CLI naming
+case "$ARCH" in
+  x86_64|amd64) ARCH_NAME="x64" ;;
+  aarch64|arm64) ARCH_NAME="arm64" ;;
+  *) echo "ERROR: Unsupported architecture: ${ARCH}"; exit 1 ;;
+esac
+
+# Map OS to Copilot CLI naming
+case "$OS" in
+  Linux) PLATFORM="linux" ;;
+  Darwin) PLATFORM="darwin" ;;
+  *) echo "ERROR: Unsupported operating system: ${OS}"; exit 1 ;;
+esac
+
+TARBALL_NAME="copilot-${PLATFORM}-${ARCH_NAME}.tar.gz"
+
+# Build download URLs
+if [ -z "$VERSION" ]; then
+  BASE_URL="https://github.com/${COPILOT_REPO}/releases/latest/download"
+else
+  # Prefix version with 'v' if not already present
+  case "$VERSION" in
+    v*) ;;
+    *) VERSION="v$VERSION" ;;
+  esac
+  BASE_URL="https://github.com/${COPILOT_REPO}/releases/download/${VERSION}"
+fi
+
+TARBALL_URL="${BASE_URL}/${TARBALL_NAME}"
+CHECKSUMS_URL="${BASE_URL}/SHA256SUMS.txt"
+
+echo "Installing GitHub Copilot CLI${VERSION:+ version $VERSION} (os: ${OS}, arch: ${ARCH})..."
+
+# Platform-portable SHA256 function
+sha256_hash() {
+  local file="$1"
+  if command -v sha256sum &>/dev/null; then
+    sha256sum "$file" | awk '{print $1}'
+  elif command -v shasum &>/dev/null; then
+    shasum -a 256 "$file" | awk '{print $1}'
+  else
+    echo "ERROR: No sha256sum or shasum found" >&2
+    exit 1
+  fi
 }
 
-# Main installation flow
-echo "Installing GitHub Copilot CLI${VERSION:+ version $VERSION}..."
+# Create temp directory with cleanup on exit
+TEMP_DIR=$(mktemp -d)
+trap 'rm -rf "$TEMP_DIR"' EXIT
+
+# Download checksums
+echo "Downloading checksums from ${CHECKSUMS_URL}..."
+curl -fsSL -o "${TEMP_DIR}/SHA256SUMS.txt" "${CHECKSUMS_URL}"
+
+# Download binary tarball
+echo "Downloading binary from ${TARBALL_URL}..."
+curl -fsSL -o "${TEMP_DIR}/${TARBALL_NAME}" "${TARBALL_URL}"
+
+# Verify checksum
+echo "Verifying SHA256 checksum for ${TARBALL_NAME}..."
+EXPECTED_CHECKSUM=$(awk -v fname="${TARBALL_NAME}" '$2 == fname {print $1; exit}' "${TEMP_DIR}/SHA256SUMS.txt" | tr 'A-F' 'a-f')
 
-# Download installer with retry logic
-if ! download_installer_with_retry; then
-  echo "ERROR: Could not download Copilot CLI installer"
+if [ -z "$EXPECTED_CHECKSUM" ]; then
+  echo "ERROR: Could not find checksum for ${TARBALL_NAME} in SHA256SUMS.txt"
   exit 1
 fi
 
-# Execute the installer with the specified version
-# Pass VERSION directly to sudo to ensure it's available to the installer script
-if [ -n "$VERSION" ]; then
-  echo "Installing Copilot CLI version $VERSION..."
-  sudo VERSION="$VERSION" bash "$INSTALLER_TEMP"
-else
-  echo "Installing latest Copilot CLI version..."
-  sudo bash "$INSTALLER_TEMP"
+ACTUAL_CHECKSUM=$(sha256_hash "${TEMP_DIR}/${TARBALL_NAME}" | tr 'A-F' 'a-f')
+
+if [ "$EXPECTED_CHECKSUM" != "$ACTUAL_CHECKSUM" ]; then
+  echo "ERROR: Checksum verification failed!"
+  echo "  Expected: $EXPECTED_CHECKSUM"
+  echo "  Got:      $ACTUAL_CHECKSUM"
+  echo "  The downloaded file may be corrupted or tampered with"
+  exit 1
 fi
 
-# Cleanup temp file
-rm -f "$INSTALLER_TEMP"
+echo "✓ Checksum verification passed for ${TARBALL_NAME}"
+
+# Extract and install binary
+echo "Installing binary to ${INSTALL_DIR}..."
+sudo tar -xz -C "${INSTALL_DIR}" -f "${TEMP_DIR}/${TARBALL_NAME}"
+sudo chmod +x "${INSTALL_DIR}/copilot"
 
 # Verify installation
 echo "Verifying Copilot CLI installation..."