diff --git a/sdk/typescript/_bundled_plugin/scripts/generate_rank_input.py b/sdk/typescript/_bundled_plugin/scripts/generate_rank_input.py
index 535fe341..d66537b4 100644
--- a/sdk/typescript/_bundled_plugin/scripts/generate_rank_input.py
+++ b/sdk/typescript/_bundled_plugin/scripts/generate_rank_input.py
@@ -660,10 +660,17 @@ def make_diff_rank_input(args: argparse.Namespace) -> None:
 
         if status == "D":
             preview = ""
+        elif path.is_symlink():
+            preview = ""
         elif path.is_file():
-            preview, is_binary = preview_for(path, args.preview_bytes)
-            if is_binary:
-                continue
+            try:
+                path.resolve(strict=True).relative_to(repo)
+            except (OSError, ValueError):
+                preview = ""
+            else:
+                preview, is_binary = preview_for(path, args.preview_bytes)
+                if is_binary:
+                    continue
         else:
             preview = ""
         rows.append({"path": rel.as_posix(), "area": args.area, "preview": preview})
diff --git a/sdk/typescript/tests-ts/diff-rank-input.test.ts b/sdk/typescript/tests-ts/diff-rank-input.test.ts
new file mode 100644
index 00000000..86b9ebfd
--- /dev/null
+++ b/sdk/typescript/tests-ts/diff-rank-input.test.ts
@@ -0,0 +1,121 @@
+import { execFileSync, spawnSync } from "node:child_process";
+import {
+  mkdirSync,
+  mkdtempSync,
+  readFileSync,
+  realpathSync,
+  rmSync,
+  symlinkSync,
+  writeFileSync,
+} from "node:fs";
+import { tmpdir } from "node:os";
+import { join } from "node:path";
+import { afterEach, expect, test } from "bun:test";
+import { PLUGIN_ROOT } from "./plugin-root.js";
+
+const temporaryRoots: string[] = [];
+
+afterEach(() => {
+  for (const root of temporaryRoots.splice(0)) {
+    rmSync(root, { recursive: true, force: true });
+  }
+});
+
+function git(repository: string, ...args: string[]): string {
+  return execFileSync(
+    "git",
+    [
+      "-c",
+      "user.name=Fixture",
+      "-c",
+      "user.email=fixture@example.com",
+      ...args,
+    ],
+    { cwd: repository, encoding: "utf8" },
+  ).trim();
+}
+
+test("diff previews stay inside the selected repository", () => {
+  const root = realpathSync(
+    mkdtempSync(join(tmpdir(), "codex-security-diff-rank-")),
+  );
+  temporaryRoots.push(root);
+  const repository = join(root, "repository");
+  const nested = join(repository, "src", "nested");
+  mkdirSync(nested, { recursive: true });
+  git(repository, "init", "-q");
+  writeFileSync(join(repository, "src", "handler.py"), "value = 1\n");
+  writeFileSync(join(repository, "src", "deleted.py"), "removed = True\n");
+  writeFileSync(join(repository, "src", "entry.py"), "handler.py");
+  writeFileSync(join(nested, "linked.py"), "value = 1\n");
+  git(repository, "add", ".");
+  const originalLink = git(repository, "hash-object", "src/entry.py");
+  git(
+    repository,
+    "update-index",
+    "--cacheinfo",
+    `120000,${originalLink},src/entry.py`,
+  );
+  git(repository, "commit", "-qm", "base");
+  const base = git(repository, "rev-parse", "HEAD");
+
+  writeFileSync(join(repository, "src", "handler.py"), "value = 2\n");
+  writeFileSync(join(repository, "src", "entry.py"), "nested/linked.py");
+  writeFileSync(join(nested, "linked.py"), "value = 2\n");
+  rmSync(join(repository, "src", "deleted.py"));
+  git(repository, "add", ".");
+  const updatedLink = git(repository, "hash-object", "src/entry.py");
+  git(
+    repository,
+    "update-index",
+    "--cacheinfo",
+    `120000,${updatedLink},src/entry.py`,
+  );
+  git(repository, "commit", "-qm", "selected changes");
+  const head = git(repository, "rev-parse", "HEAD");
+
+  const externalFixture = join(root, "synthetic-fixture");
+  mkdirSync(externalFixture);
+  writeFileSync(join(externalFixture, "linked.py"), "synthetic = True\n");
+  rmSync(nested, { recursive: true });
+  symlinkSync(externalFixture, nested, "junction");
+
+  const python = Bun.which("python3") ?? Bun.which("python") ?? Bun.which("py");
+  expect(python).not.toBeNull();
+  const output = join(root, "rank-input.jsonl");
+  const result = spawnSync(
+    python!,
+    [
+      "-B",
+      join(PLUGIN_ROOT, "scripts", "generate_rank_input.py"),
+      "make-diff-rank-input",
+      "--repo",
+      repository,
+      "--base",
+      base,
+      "--head",
+      head,
+      "--out",
+      output,
+    ],
+    { encoding: "utf8" },
+  );
+
+  expect(result.status, result.stderr).toBe(0);
+  const rows = readFileSync(output, "utf8")
+    .trim()
+    .split("\n")
+    .map((row) => JSON.parse(row) as { path: string; preview: string });
+  expect(rows.map((row) => row.path)).toEqual([
+    "src/deleted.py",
+    "src/entry.py",
+    "src/handler.py",
+    "src/nested/linked.py",
+  ]);
+  expect(rows.find((row) => row.path === "src/handler.py")?.preview).toBe(
+    "value = 2",
+  );
+  expect(rows.find((row) => row.path === "src/nested/linked.py")?.preview).toBe(
+    "",
+  );
+});