diff --git a/media_shrinker.py b/media_shrinker.py
index 1cc2a9f..41c9122 100644
--- a/media_shrinker.py
+++ b/media_shrinker.py
@@ -465,7 +465,10 @@ def probe_media(
         "-i",
         str(source_path),
     ]
-    completed = subprocess.run(command, check=False, capture_output=True, text=True)
+    try:
+        completed = subprocess.run(command, check=False, capture_output=True, text=True, timeout=30.0)
+    except subprocess.TimeoutExpired as exc:
+        raise MediaShrinkerError(f"ffprobe timed out for {source_path}") from exc
     if completed.returncode != 0:
         raise MediaShrinkerError(
             f"ffprobe failed for {source_path}: {completed.stderr.strip()}"
@@ -518,17 +521,21 @@ def detect_silence_intervals(
 ) -> list[SilenceInterval]:
     """Run ffmpeg silencedetect and return paired silence intervals."""
 
-    completed = subprocess.run(
-        build_silencedetect_command(
-            source_path,
-            ffmpeg_path=ffmpeg_path,
-            silence_noise=silence_noise,
-            silence_min_duration_seconds=silence_min_duration_seconds,
-        ),
-        check=False,
-        capture_output=True,
-        text=True,
-    )
+    try:
+        completed = subprocess.run(
+            build_silencedetect_command(
+                source_path,
+                ffmpeg_path=ffmpeg_path,
+                silence_noise=silence_noise,
+                silence_min_duration_seconds=silence_min_duration_seconds,
+            ),
+            check=False,
+            capture_output=True,
+            text=True,
+            timeout=180.0,
+        )
+    except subprocess.TimeoutExpired as exc:
+        raise MediaShrinkerError(f"silencedetect timed out for {source_path}") from exc
     if completed.returncode != 0:
         raise MediaShrinkerError(
             f"silencedetect failed for {source_path}: {completed.stderr.strip()}"
@@ -643,12 +650,16 @@ def download_from_icloud(source_path: Path, *, brctl_path: str = "brctl") -> Non
         raise MediaShrinkerError(
             f"iCloud download requested but '{brctl_path}' was not found"
         )
-    completed = subprocess.run(
-        build_icloud_download_command(source_path, brctl_path=brctl_path),
-        check=False,
-        capture_output=True,
-        text=True,
-    )
+    try:
+        completed = subprocess.run(
+            build_icloud_download_command(source_path, brctl_path=brctl_path),
+            check=False,
+            capture_output=True,
+            text=True,
+            timeout=300.0,
+        )
+    except subprocess.TimeoutExpired as exc:
+        raise MediaShrinkerError(f"iCloud download timed out for {source_path}") from exc
     if completed.returncode != 0:
         raise MediaShrinkerError(
             f"iCloud download failed for {source_path}: {completed.stderr.strip()}"
@@ -1550,8 +1561,10 @@ def _execute_plan(
         )
         try:
             completed = subprocess.run(
-                command, check=False, capture_output=True, text=True
+                command, check=False, capture_output=True, text=True, timeout=1800.0
             )
+        except subprocess.TimeoutExpired as exc:
+            raise MediaShrinkerError(f"ffmpeg conversion timed out for {source}") from exc
         except FileNotFoundError as exc:
             raise MediaShrinkerError(f"ffmpeg not found: {ffmpeg_path}") from exc
 
@@ -1618,12 +1631,16 @@ def _copy_macos_creation_time(
     creation_date = datetime.fromtimestamp(float(birthtime)).strftime(
         "%m/%d/%Y %H:%M:%S"
     )
-    subprocess.run(
-        [setfile_path, "-d", creation_date, str(dest.resolve())],
-        check=False,
-        capture_output=True,
-        text=True,
-    )
+    try:
+        subprocess.run(
+            [setfile_path, "-d", creation_date, str(dest.resolve())],
+            check=False,
+            capture_output=True,
+            text=True,
+            timeout=30.0,
+        )
+    except subprocess.TimeoutExpired:
+        pass
 
 
 def _format_result(root: Path, result: ConversionResult) -> str:
diff --git a/tests/test_security.py b/tests/test_security.py
index 6ec6aff..af1edef 100644
--- a/tests/test_security.py
+++ b/tests/test_security.py
@@ -2,6 +2,7 @@
 from pathlib import Path
 from unittest.mock import MagicMock, patch
 
+import subprocess
 from media_shrinker import build_silencedetect_command, MediaShrinkerError, probe_media
 
 class SecurityTests(unittest.TestCase):
@@ -33,5 +34,14 @@ def test_probe_media_uses_explicit_input_flag_for_dash_prefixed_path(
         input_index = command.index("-i")
         self.assertEqual(command[input_index + 1], str(source_path))
 
+    @patch("media_shrinker.subprocess.run")
+    def test_probe_media_enforces_timeout(self, mock_run: MagicMock):
+        mock_run.side_effect = subprocess.TimeoutExpired(cmd=["ffprobe"], timeout=30.0)
+        with patch.object(Path, "stat") as mock_stat:
+            mock_stat.return_value = MagicMock(st_size=10)
+            with self.assertRaises(MediaShrinkerError) as cm:
+                probe_media(Path("test.wav"))
+        self.assertIn("timed out", str(cm.exception))
+
 if __name__ == "__main__":
     unittest.main()