diff --git a/.gitea/workflows/custom-release.yml b/.gitea/workflows/custom-release.yml
index 1bd3fddd9..6f2a454d1 100644
--- a/.gitea/workflows/custom-release.yml
+++ b/.gitea/workflows/custom-release.yml
@@ -25,7 +25,7 @@ on:
 
 jobs:
   build-custom-release:
-    runs-on: ubuntu-latest
+    runs-on: ffmini_macos_arm64
     steps:
       - name: Check out repository
         uses: actions/checkout@v4
@@ -51,6 +51,26 @@ jobs:
         env:
           GITEA_TOKEN: ${{ secrets.GITEA_TOKEN }}
 
+      - name: Import Developer ID certificate
+        run: |
+          set -euo pipefail
+          keychain_path="$RUNNER_TEMP/syncthing-release-signing.keychain-db"
+          keychain_password="$(openssl rand -hex 24)"
+          certificate_path="$RUNNER_TEMP/developer-id-application.p12"
+
+          printf '%s' "$DEVELOPER_ID_APPLICATION_P12_BASE64" | base64 -D > "$certificate_path"
+          security create-keychain -p "$keychain_password" "$keychain_path"
+          security set-keychain-settings -lut 21600 "$keychain_path"
+          security unlock-keychain -p "$keychain_password" "$keychain_path"
+          security import "$certificate_path" -k "$keychain_path" -P "$DEVELOPER_ID_APPLICATION_P12_PASSWORD" -T /usr/bin/codesign -T /usr/bin/security
+          security list-keychains -d user -s "$keychain_path" $(security list-keychains -d user | sed 's/[ "]//g')
+          security set-key-partition-list -S apple-tool:,apple:,codesign: -s -k "$keychain_password" "$keychain_path"
+
+          echo "CUSTOM_RELEASE_KEYCHAIN_PATH=$keychain_path" >> "$GITHUB_ENV"
+        env:
+          DEVELOPER_ID_APPLICATION_P12_BASE64: ${{ secrets.DEVELOPER_ID_APPLICATION_P12_BASE64 }}
+          DEVELOPER_ID_APPLICATION_P12_PASSWORD: ${{ secrets.DEVELOPER_ID_APPLICATION_P12_PASSWORD }}
+
       - name: Build patched Syncthing release
         run: ./scripts/update-custom-release.sh
         env:
@@ -59,7 +79,15 @@ jobs:
           CUSTOM_RELEASE_PUSH: "1"
           CUSTOM_RELEASE_PUSH_BRANCH: "0"
           CUSTOM_RELEASE_REMOTE: origin
-          CUSTOM_RELEASE_BUILDS: "darwin/amd64/zip darwin/arm64/zip linux/amd64/tar linux/arm64/tar"
-          CUSTOM_RELEASE_CGO_ENABLED: "0"
+          CUSTOM_RELEASE_BUILDS: "darwin/arm64/zip/1 linux/amd64/tar/0 linux/arm64/tar/0"
+          CUSTOM_RELEASE_CODESIGN_IDENTITY: "Developer ID Application: Felix Foertsch (NG5W75WE8U)"
+          CUSTOM_RELEASE_CODESIGN_TEAM_ID: "NG5W75WE8U"
           CUSTOM_RELEASE_CREATE_GITEA_RELEASE: "1"
           CUSTOM_RELEASE_TEA_REPO: felixfoertsch/syncthing
+
+      - name: Delete temporary keychain
+        if: always()
+        run: |
+          if [ -n "${CUSTOM_RELEASE_KEYCHAIN_PATH:-}" ]; then
+            security delete-keychain "$CUSTOM_RELEASE_KEYCHAIN_PATH" || true
+          fi
diff --git a/scripts/tests/test-custom-release-macos-runner.bats b/scripts/tests/test-custom-release-macos-runner.bats
new file mode 100644
index 000000000..381ebfaa6
--- /dev/null
+++ b/scripts/tests/test-custom-release-macos-runner.bats
@@ -0,0 +1,71 @@
+#!/usr/bin/env bats
+
+setup() {
+	REPO_ROOT="$(git rev-parse --show-toplevel)"
+	WORKFLOW="$REPO_ROOT/.gitea/workflows/custom-release.yml"
+	RELEASE_SCRIPT="$REPO_ROOT/scripts/update-custom-release.sh"
+}
+
+@test "custom release runs as one job on ffmini macos runner" {
+	run rg -n 'runs-on:[[:space:]]*ffmini_macos_arm64' "$WORKFLOW"
+	[ "$status" -eq 0 ]
+
+	run rg -n 'ubuntu-latest' "$WORKFLOW"
+	[ "$status" -ne 0 ]
+
+	run rg -n 'actions/upload-artifact' "$WORKFLOW"
+	[ "$status" -ne 0 ]
+}
+
+@test "custom release workflow imports developer id signing material into temporary keychain" {
+	run rg -n 'DEVELOPER_ID_APPLICATION_P12_BASE64' "$WORKFLOW"
+	[ "$status" -eq 0 ]
+
+	run rg -n 'DEVELOPER_ID_APPLICATION_P12_PASSWORD' "$WORKFLOW"
+	[ "$status" -eq 0 ]
+
+	run rg -n 'security create-keychain' "$WORKFLOW"
+	[ "$status" -eq 0 ]
+
+	run rg -n 'security import' "$WORKFLOW"
+	[ "$status" -eq 0 ]
+
+	run rg -n 'security delete-keychain' "$WORKFLOW"
+	[ "$status" -eq 0 ]
+}
+
+@test "custom release carries per-target cgo mode" {
+	run rg -n 'darwin/arm64/zip/1' "$WORKFLOW" "$RELEASE_SCRIPT"
+	[ "$status" -eq 0 ]
+
+	run rg -n 'linux/amd64/tar/0' "$WORKFLOW" "$RELEASE_SCRIPT"
+	[ "$status" -eq 0 ]
+
+	run rg -n 'CUSTOM_RELEASE_CGO_ENABLED' "$WORKFLOW"
+	[ "$status" -ne 0 ]
+}
+
+@test "custom release signs darwin assets with hardened runtime and timestamp" {
+	run rg -n 'codesign .*--options runtime .*--timestamp' "$RELEASE_SCRIPT"
+	[ "$status" -eq 0 ]
+
+	run rg -n 'Developer ID Application' "$WORKFLOW" "$RELEASE_SCRIPT"
+	[ "$status" -eq 0 ]
+
+	run rg -n 'CUSTOM_RELEASE_CODESIGN_IDENTITY' "$WORKFLOW" "$RELEASE_SCRIPT"
+	[ "$status" -eq 0 ]
+}
+
+@test "custom release validates darwin binaries before publishing" {
+	run rg -n 'modernc-sqlite' "$RELEASE_SCRIPT"
+	[ "$status" -eq 0 ]
+
+	run rg -n 'codesign --verify --strict --verbose=2' "$RELEASE_SCRIPT"
+	[ "$status" -eq 0 ]
+
+	run rg -n 'TeamIdentifier=NG5W75WE8U|TeamIdentifier.*NG5W75WE8U' "$RELEASE_SCRIPT"
+	[ "$status" -eq 0 ]
+
+	run rg -n 'spctl -a -vv --type execute' "$RELEASE_SCRIPT"
+	[ "$status" -eq 0 ]
+}
diff --git a/scripts/update-custom-release.sh b/scripts/update-custom-release.sh
index d302b397f..b7e01483d 100755
--- a/scripts/update-custom-release.sh
+++ b/scripts/update-custom-release.sh
@@ -12,7 +12,9 @@ dist_dir="${CUSTOM_RELEASE_DIST_DIR:-dist}"
 target="${CUSTOM_RELEASE_TARGET:-syncthing}"
 archive_kind="${CUSTOM_RELEASE_ARCHIVE:-tar}"
 build_specs="${CUSTOM_RELEASE_BUILDS:-}"
-cgo_enabled="${CUSTOM_RELEASE_CGO_ENABLED:-0}"
+default_cgo_enabled="${CUSTOM_RELEASE_CGO_ENABLED:-0}"
+codesign_identity="${CUSTOM_RELEASE_CODESIGN_IDENTITY:-}"
+codesign_team_id="${CUSTOM_RELEASE_CODESIGN_TEAM_ID:-NG5W75WE8U}"
 push_release="${CUSTOM_RELEASE_PUSH:-0}"
 push_branch="${CUSTOM_RELEASE_PUSH_BRANCH:-0}"
 push_remote="${CUSTOM_RELEASE_REMOTE:-origin}"
@@ -148,6 +150,14 @@ rebuild_assets_once() {
 	assets_rebuilt=1
 }
 
+format_build_specs() {
+	local spec
+
+	for spec in $build_specs; do
+		printf -- '- %s\n' "$spec"
+	done
+}
+
 build_release() {
 	local custom_tag="$1"
 
@@ -170,7 +180,7 @@ build_release() {
 Syncthing $upstream_tag with the local patches applied.
 
 Builds:
-$(printf -- '- %s\n' $build_specs)
+$(format_build_specs)
 
 Patches:
 $(printf -- '- %s\n' "${patch_files[@]}")
@@ -197,9 +207,11 @@ build_one() {
 	local goos
 	local goarch
 	local kind
+	local cgo_enabled
 
-	IFS=/ read -r goos goarch kind <<< "$spec"
+	IFS=/ read -r goos goarch kind cgo_enabled <<< "$spec"
 	[[ -n "$goos" && -n "$goarch" && -n "$kind" ]] || die "invalid build spec: $spec"
+	cgo_enabled="${cgo_enabled:-$default_cgo_enabled}"
 
 	log "Building $target for $goos/$goarch as $kind with CGO_ENABLED=$cgo_enabled"
 
@@ -207,10 +219,16 @@ build_one() {
 		tar|zip)
 			local archive
 			archive="$(CGO_ENABLED="$cgo_enabled" go run build.go -version "$custom_tag" -goos "$goos" -goarch "$goarch" "$kind" "$target" | tail -n 1)"
+			if [[ "$goos" == "darwin" ]]; then
+				sign_and_validate_darwin_archive "$archive" "$kind"
+			fi
 			mv "$archive" "$dist_dir/"
 			;;
 		binary)
 			CGO_ENABLED="$cgo_enabled" go run build.go -version "$custom_tag" -goos "$goos" -goarch "$goarch" -build-out "$dist_dir/$target-$goos-$goarch" build "$target"
+			if [[ "$goos" == "darwin" ]]; then
+				sign_and_validate_darwin_binary "$dist_dir/$target-$goos-$goarch"
+			fi
 			;;
 		*)
 			die "unknown build archive kind in $spec"
@@ -218,6 +236,91 @@ build_one() {
 	esac
 }
 
+find_release_binary() {
+	local root="$1"
+	local candidate
+
+	while IFS= read -r candidate; do
+		if [[ -x "$candidate" ]]; then
+			printf '%s\n' "$candidate"
+			return
+		fi
+	done < <(find "$root" -type f -name "$target")
+
+	die "could not find executable $target in $root"
+}
+
+sign_and_validate_darwin_archive() {
+	local archive="$1"
+	local kind="$2"
+	local tmp
+	local archive_abs
+	local binary
+
+	[[ -n "$codesign_identity" ]] || die "CUSTOM_RELEASE_CODESIGN_IDENTITY is required for darwin builds"
+
+	tmp="$(mktemp -d)"
+	archive_abs="$(cd "$(dirname "$archive")" && pwd -P)/$(basename "$archive")"
+	case "$kind" in
+		zip)
+			unzip -q "$archive_abs" -d "$tmp"
+			;;
+		tar)
+			tar -xf "$archive_abs" -C "$tmp"
+			;;
+		*)
+			die "cannot sign archive kind $kind"
+			;;
+	esac
+
+	binary="$(find_release_binary "$tmp")"
+	sign_and_validate_darwin_binary "$binary"
+
+	rm -f "$archive_abs"
+	case "$kind" in
+		zip)
+			(
+				cd "$tmp"
+				zip -qr "$archive_abs" .
+			)
+			;;
+		tar)
+			(
+				cd "$tmp"
+				tar -czf "$archive_abs" .
+			)
+			;;
+	esac
+	rm -rf "$tmp"
+}
+
+sign_and_validate_darwin_binary() {
+	local binary="$1"
+	local version_output
+	local codesign_details
+
+	[[ -n "$codesign_identity" ]] || die "CUSTOM_RELEASE_CODESIGN_IDENTITY is required for darwin builds"
+
+	codesign --force --sign "$codesign_identity" --options runtime --timestamp "$binary"
+
+	version_output="$("$binary" --version)"
+	if [[ "$version_output" == *modernc-sqlite* ]]; then
+		die "darwin build unexpectedly reports [modernc-sqlite]: $version_output"
+	fi
+
+	codesign --verify --strict --verbose=2 "$binary"
+	codesign_details="$(codesign -dv --verbose=4 "$binary" 2>&1)"
+	if [[ "$codesign_team_id" == "NG5W75WE8U" && "$codesign_details" != *"TeamIdentifier=NG5W75WE8U"* ]]; then
+		printf '%s\n' "$codesign_details" >&2
+		die "darwin build is not signed by TeamIdentifier=NG5W75WE8U"
+	fi
+	if [[ "$codesign_details" != *"TeamIdentifier=$codesign_team_id"* ]]; then
+		printf '%s\n' "$codesign_details" >&2
+		die "darwin build is not signed by TeamIdentifier=$codesign_team_id"
+	fi
+	spctl -a -vv --type execute "$binary"
+}
+
 push_refs() {
 	local branch="$1"
 	local custom_tag="$2"