diff --git a/build_test.go b/build_test.go
index 6117bf2..2e7f58c 100644
--- a/build_test.go
+++ b/build_test.go
@@ -520,3 +520,32 @@ func (w *sourceChangeWriter) Write(p []byte) (int, error) {
 	}
 	return len(p), nil
 }
+
+func TestCandidateBuildDoesNotRequireWritableRepositoryParent(t *testing.T) {
+	if runtime.GOOS == "windows" || os.Getuid() == 0 {
+		t.Skip("requires ordinary Unix permission checks")
+	}
+	repository := newBuildConsumer(t, `package main
+import("fmt";"gitea.maximumdirect.net/eric/ReleaseKit/buildinfo")
+func main(){fmt.Println("fixture",buildinfo.Version())}
+`)
+	writeBuildFixture(t, repository, "docs/releases/v1.2.3.md", "# Fixture v1.2.3\n")
+	buildGit(t, repository, "add", "--all")
+	buildGit(t, repository, "commit", "-m", "note")
+	parent := t.TempDir()
+	moved := filepath.Join(parent, "repo")
+	if err := os.Rename(repository, moved); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.Chmod(parent, 0555); err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(func() { os.Chmod(parent, 0700) })
+	_, err := releasekit.Check(context.Background(), releasekit.ReleaseRequest{RepositoryDir: moved, Product: "Fixture", Version: "v1.2.3", Validate: func(context.Context, releasekit.Candidate) error { return nil }, Build: &releasekit.BuildSpec{MainPackage: "./cmd/app", BinaryName: "fixture", Targets: []releasekit.Target{{OS: runtime.GOOS, Arch: runtime.GOARCH}}}})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if status := buildGit(t, moved, "status", "--porcelain"); status != "" {
+		t.Fatalf("candidate dirtied: %s", status)
+	}
+}
diff --git a/cmd/releasekit/internal/cli/config.go b/cmd/releasekit/internal/cli/config.go
index 8c6863b..71c1e35 100644
--- a/cmd/releasekit/internal/cli/config.go
+++ b/cmd/releasekit/internal/cli/config.go
@@ -14,6 +14,7 @@ import (
 	"strings"
 
 	"gitea.maximumdirect.net/eric/ReleaseKit/internal/process"
+	"gitea.maximumdirect.net/eric/ReleaseKit/internal/tempdir"
 )
 
 const Usage = "usage: releasekit version\n       releasekit check [--repo DIR] [--config FILE] VERSION\n       releasekit publish [--repo DIR] [--config FILE] VERSION\n       releasekit build [--repo DIR] [--config FILE] [--output DIR] VERSION\n       releasekit deliver [--repo DIR] [--config FILE] [--assets DIR] VERSION"
@@ -202,3 +203,8 @@ func RunChecks(ctx context.Context, repoDir string, checks []CheckCommand, owned
 	}
 	return nil
 }
+
+// TemporaryBuildDir allocates command-owned storage outside its source checkout.
+func TemporaryBuildDir(repository string) (string, error) {
+	return tempdir.Outside(repository, "releasekit-delivery-")
+}
diff --git a/cmd/releasekit/main.go b/cmd/releasekit/main.go
index 0ca5977..f2f1d7c 100644
--- a/cmd/releasekit/main.go
+++ b/cmd/releasekit/main.go
@@ -197,7 +197,7 @@ func runDelivery(ctx context.Context, invocation cli.Invocation, stdout, stderr
 				fmt.Fprintf(stderr, "resolve repository directory: %v\n", resolveErr)
 				return 1
 			}
-			temporaryDir, err = os.MkdirTemp(filepath.Dir(repositoryDir), ".releasekit-delivery-")
+			temporaryDir, err = cli.TemporaryBuildDir(repositoryDir)
 			if err != nil {
 				fmt.Fprintf(stderr, "create temporary build directory: %v\n", err)
 				return 1
diff --git a/cmd/releasekit/main_test.go b/cmd/releasekit/main_test.go
index 9256f07..0fa9bfb 100644
--- a/cmd/releasekit/main_test.go
+++ b/cmd/releasekit/main_test.go
@@ -762,3 +762,33 @@ func main(){fmt.Println("fixture",buildinfo.Version())}
 		t.Fatalf("stale receipt remains: %v", err)
 	}
 }
+
+func TestTemporaryDeliveryBuildDoesNotRequireWritableRepositoryParent(t *testing.T) {
+	if runtime.GOOS == "windows" || os.Getuid() == 0 {
+		t.Skip("requires ordinary Unix permission checks")
+	}
+	repository := newDeliveryBuildRepository(t)
+	state := &deliveryServerState{}
+	server := newDeliveryServer(t, state)
+	defer server.Close()
+	writeDeliveryProfile(t, repository, cli.Settings{Product: "Example Product", Build: &cli.BuildSettings{MainPackage: ".", BinaryName: "helper", Targets: []string{"linux/amd64"}}, Delivery: &cli.DeliverySettings{BaseURL: server.URL, Owner: "owner", Repository: "example"}})
+	state.commit = cliGitOutput(t, repository, "rev-parse", "HEAD")
+	cliGitRun(t, repository, "tag", "v1.2.3")
+	parent := t.TempDir()
+	moved := filepath.Join(parent, "repo")
+	if err := os.Rename(repository, moved); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.Chmod(parent, 0555); err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(func() { os.Chmod(parent, 0700) })
+	t.Setenv("RELEASEKIT_GITEA_TOKEN", "fixture-token")
+	var stdout, stderr bytes.Buffer
+	if status := run(context.Background(), []string{"deliver", "--repo", moved, "v1.2.3"}, &stdout, &stderr); status != 0 {
+		t.Fatalf("status=%d %s", status, stderr.String())
+	}
+	if status := cliGitOutput(t, moved, "status", "--porcelain"); status != "" {
+		t.Fatalf("source dirtied: %s", status)
+	}
+}
diff --git a/docs/internal/overview.md b/docs/internal/overview.md
index 93c7bf5..ff72890 100644
--- a/docs/internal/overview.md
+++ b/docs/internal/overview.md
@@ -39,6 +39,7 @@ these implemented packages:
 | `internal/delivery` | Tagged-checkout verification, artifact inventory/hash validation, manifest assembly, and coordination of hosted delivery results. |
 | `internal/git` | Git command boundary, push-destination resolution, exact ref inspection, and tag operations. |
 | `internal/gitea` | Gitea API transport, hosted release pages, asset inspection, manifests, and uploads. |
+| `internal/tempdir` | Disposable system temporary storage outside source worktrees. |
 | `internal/process` | Cancellable child-process execution with per-command environment overlays. |
 | `internal/publish` | Publication guards, one validation run, annotated tag creation, push, and recovery state. |
 | `internal/runtimeinfo` | Private version lookup used by the runtime facade. |
diff --git a/docs/roadmap/remediation.md b/docs/roadmap/remediation.md
index a62c16c..89d1138 100644
--- a/docs/roadmap/remediation.md
+++ b/docs/roadmap/remediation.md
@@ -230,6 +230,8 @@ offline suite, and compiled-export/import checks pass.
 
 ### R6 — Medium: Builds require a writable parent of the repository
 
+Status: Resolved.
+
 Category: Inadvertently strengthened filesystem prerequisite.
 
 **Evidence:** [Candidate builds](../../internal/build/candidate.go), around line 21,
@@ -250,6 +252,11 @@ adding broad output-directory restrictions.
 read-only repository parent and a usable system temporary directory. Generated
 candidate output still leaves the worktree clean.
 
+**Resolution:** Candidate and CLI delivery builds use shared system temporary
+storage allocated by `internal/tempdir`, with worktree containment checks and
+caller-owned cleanup. Regressions execute both operations with read-only
+repository parents and confirm clean worktrees. Affected suites pass.
+
 ### R7 — Medium: Attachment origin restrictions exceed credential isolation
 
 Category: Inadvertently strengthened prohibition.
diff --git a/internal/build/candidate.go b/internal/build/candidate.go
index 828c09f..16c6461 100644
--- a/internal/build/candidate.go
+++ b/internal/build/candidate.go
@@ -5,10 +5,9 @@ import (
 	"fmt"
 	"io"
 	"os"
-	"path/filepath"
-	"strings"
 
 	"gitea.maximumdirect.net/eric/ReleaseKit/internal/candidate"
+	"gitea.maximumdirect.net/eric/ReleaseKit/internal/tempdir"
 )
 
 func CandidateCallback(spec *Spec, output io.Writer) func(context.Context, candidate.Candidate) error {
@@ -18,18 +17,11 @@ func CandidateCallback(spec *Spec, output io.Writer) func(context.Context, candi
 	selected := *spec
 	selected.Targets = append([]Target(nil), spec.Targets...)
 	return func(ctx context.Context, captured candidate.Candidate) error {
-		temporaryDir, err := os.MkdirTemp(filepath.Dir(captured.RepositoryDir), ".releasekit-candidate-build-")
+		temporaryDir, err := tempdir.Outside(captured.RepositoryDir, "releasekit-candidate-build-")
 		if err != nil {
 			return fmt.Errorf("create temporary candidate build output: %w", err)
 		}
 		defer os.RemoveAll(temporaryDir)
-		relative, err := filepath.Rel(captured.RepositoryDir, temporaryDir)
-		if err != nil {
-			return fmt.Errorf("verify temporary candidate build output: %w", err)
-		}
-		if relative == "." || relative != ".." && !strings.HasPrefix(relative, ".."+string(filepath.Separator)) {
-			return fmt.Errorf("temporary candidate build output %q is inside the repository", temporaryDir)
-		}
 		_, err = Build(ctx, Request{
 			RepositoryDir: captured.RepositoryDir,
 			Version:       captured.Version,
diff --git a/internal/tempdir/tempdir.go b/internal/tempdir/tempdir.go
new file mode 100644
index 0000000..0eed265
--- /dev/null
+++ b/internal/tempdir/tempdir.go
@@ -0,0 +1,33 @@
+// Package tempdir allocates disposable storage outside a source worktree.
+package tempdir
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+// Outside uses the system temporary directory and leaves cleanup to its caller.
+func Outside(repositoryDir, pattern string) (string, error) {
+	directory, err := os.MkdirTemp("", pattern)
+	if err != nil {
+		return "", err
+	}
+	repository, err := filepath.Abs(repositoryDir)
+	if err == nil && !strings.EqualFold(filepath.VolumeName(repository), filepath.VolumeName(directory)) {
+		return directory, nil
+	}
+	if err == nil {
+		var relative string
+		relative, err = filepath.Rel(repository, directory)
+		if err == nil && (relative == "." || relative != ".." && !strings.HasPrefix(relative, ".."+string(filepath.Separator))) {
+			err = fmt.Errorf("temporary storage %q is inside repository %q; select an external temporary directory", directory, repository)
+		}
+	}
+	if err != nil {
+		os.RemoveAll(directory)
+		return "", err
+	}
+	return directory, nil
+}