diff --git a/packages/web/server/lib/git/service.js b/packages/web/server/lib/git/service.js
index 6c4fb52b..8e67a445 100644
--- a/packages/web/server/lib/git/service.js
+++ b/packages/web/server/lib/git/service.js
@@ -3663,6 +3663,7 @@ export async function removeWorktree(directory, input = {}) {
   if (targetCanonical === primaryCanonical) {
     throw new Error('Cannot remove the primary workspace');
   }
+  const worktreeRootCanonical = await canonicalPath(context.worktreeRoot);
 
   const entries = await listWorktreeEntries(context.primaryWorktree);
   const matchedEntry = await (async () => {
@@ -3679,6 +3680,10 @@ export async function removeWorktree(directory, input = {}) {
   })();
 
   if (!matchedEntry?.worktree) {
+    if (targetCanonical === worktreeRootCanonical || !isInsideOrSameDirectory(worktreeRootCanonical, targetCanonical)) {
+      throw new Error('Cannot remove unmanaged worktree directory');
+    }
+
     const targetExists = await checkPathExists(targetDirectory);
     if (targetExists) {
       await fsp.rm(targetDirectory, { recursive: true, force: true });
diff --git a/packages/web/server/lib/git/service.test.js b/packages/web/server/lib/git/service.test.js
index 96814df7..977a093b 100644
--- a/packages/web/server/lib/git/service.test.js
+++ b/packages/web/server/lib/git/service.test.js
@@ -9,6 +9,7 @@ import {
   checkoutCommit,
   cherryPick,
   getStatus,
+  removeWorktree,
   resetToCommit,
   resolveBaseRefForLog,
   revertCommit,
@@ -139,6 +140,46 @@ describe('getStatus', () => {
   });
 });
 
+// ---------------------------------------------------------------------------
+// removeWorktree
+// ---------------------------------------------------------------------------
+
+describe('removeWorktree', () => {
+  it('refuses orphan cleanup outside the managed worktree root', async () => {
+    if (!canRunGit()) return;
+
+    const previousXdgDataHome = process.env.XDG_DATA_HOME;
+    const dataHome = createTempDir();
+    process.env.XDG_DATA_HOME = dataHome;
+
+    try {
+      const repo = createTempDir();
+      const sentinel = createTempDir();
+      const canary = path.join(sentinel, 'canary.txt');
+
+      runGit(repo, ['init', '-b', 'main']);
+      runGit(repo, ['config', 'user.email', 'test@example.com']);
+      runGit(repo, ['config', 'user.name', 'Test User']);
+      fs.writeFileSync(path.join(repo, 'README.md'), '# Test\n');
+      runGit(repo, ['add', 'README.md']);
+      runGit(repo, ['commit', '-m', 'Initial commit']);
+      fs.writeFileSync(canary, 'sentinel');
+
+      await expect(removeWorktree(repo, {
+        directory: sentinel,
+        deleteLocalBranch: false,
+      })).rejects.toThrow('Cannot remove unmanaged worktree directory');
+      expect(fs.existsSync(canary)).toBe(true);
+    } finally {
+      if (previousXdgDataHome === undefined) {
+        delete process.env.XDG_DATA_HOME;
+      } else {
+        process.env.XDG_DATA_HOME = previousXdgDataHome;
+      }
+    }
+  });
+});
+
 // ---------------------------------------------------------------------------
 // checkoutCommit
 // ---------------------------------------------------------------------------