diff --git a/.github/scripts/strip-bundled-npm.sh b/.github/scripts/strip-bundled-npm.sh
new file mode 100755
index 00000000000..cd3981b9bc9
--- /dev/null
+++ b/.github/scripts/strip-bundled-npm.sh
@@ -0,0 +1,40 @@
+#!/usr/bin/env bash
+# Fork-only: remove the npm and corepack bundled with Node from a runner layout.
+# The runner only executes externals/node*/bin/node; npm and corepack are unused and pin
+# vulnerable dependencies (tar, minimatch, undici, ...) that would otherwise ship in every
+# package. Lives outside src/ so upstream merges stay clean.
+#
+# Usage: strip-bundled-npm.sh <layout-dir> <runtime>
+set -euo pipefail
+layout="$1"
+runtime="$2"
+
+shopt -s nullglob
+nodes=("$layout"/externals/node*/)
+if [ ${#nodes[@]} -eq 0 ]; then
+  echo "::error::No bundled Node found in $layout/externals"
+  exit 1
+fi
+for d in "${nodes[@]}"; do
+  rm -rf "${d}lib/node_modules/npm" "${d}lib/node_modules/corepack" \
+    "${d}bin/npm" "${d}bin/npx" "${d}bin/corepack"
+done
+leftover="$(find "$layout/externals" \( -path '*/node_modules/npm' -o -path '*/node_modules/corepack' \
+  -o -path '*/bin/npm' -o -path '*/bin/npx' -o -path '*/bin/corepack' \) -print -quit)"
+if [ -n "$leftover" ]; then
+  echo "::error::npm or corepack is still bundled in $layout/externals: $leftover"
+  exit 1
+fi
+for d in "${nodes[@]}"; do
+  if [ ! -x "${d}bin/node" ]; then
+    echo "::error::${d}bin/node is missing"
+    exit 1
+  fi
+  # Alpine builds need musl, and linux-arm (armv7l) cannot run on the arm64 build host;
+  # the package tests cover those.
+  case "$d" in *_alpine/) continue ;; esac
+  if [ "$runtime" != linux-arm ]; then
+    version="$("${d}bin/node" --version)"
+    echo "${d}bin/node $version"
+  fi
+done
diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 5c76e0c89f9..41a357425a8 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -70,6 +70,10 @@ jobs:
         ./dev.sh layout Release ${{ matrix.runtime }}
       working-directory: src
 
+    # Fork-only: see .github/scripts/strip-bundled-npm.sh.
+    - name: Strip bundled npm and corepack
+      run: .github/scripts/strip-bundled-npm.sh _layout ${{ matrix.runtime }}
+
     # Run tests
     - name: L0
       run: |
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index c4f4fedb007..6f8293d56fb 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -108,6 +108,10 @@ jobs:
         ./dev.sh layout Release ${{ matrix.runtime }}
       working-directory: src
 
+    # Fork-only: see .github/scripts/strip-bundled-npm.sh.
+    - name: Strip bundled npm and corepack
+      run: .github/scripts/strip-bundled-npm.sh _layout ${{ matrix.runtime }}
+
     # Create runner package tar.gz/zip
     - name: Package Release
       if: github.event_name != 'pull_request'