diff --git a/deploy/services/unzip.py b/deploy/services/unzip.py
index b4b0b67..224f897 100644
--- a/deploy/services/unzip.py
+++ b/deploy/services/unzip.py
@@ -1,5 +1,23 @@
 """Unzip service — extract files from ZIP archive (no DB, no parse)."""
-import zipfile, io, base64
+import zipfile, io, base64, os
+
+MAX_FILES = 500
+MAX_UNCOMPRESSED = 500 * 1024 * 1024  # 500 MB total
+MAX_RATIO = 100  # max compression ratio (uncompressed/compressed)
+
+
+def _sanitize_zip_name(name: str) -> str | None:
+    """Decode cp437→utf8, strip path traversal, return safe name or None."""
+    # Decode cp437 filenames (common in ZIPs from Windows)
+    try:
+        name = name.encode("cp437").decode("utf-8", errors="replace")
+    except (UnicodeDecodeError, UnicodeEncodeError):
+        pass
+    # Strip directory prefixes and path traversal
+    name = os.path.basename(name)
+    if not name or name.endswith("/") or ".." in name or "/" in name or "\\" in name:
+        return None
+    return name
 
 
 def handle_unzip(rfile, content_length):
@@ -19,11 +37,31 @@ def handle_unzip(rfile, content_length):
     zip_data = raw[zip_start:]
 
     files = []
+    total_uncompressed = 0
     with zipfile.ZipFile(io.BytesIO(zip_data)) as zf:
-        for name in zf.namelist():
-            if name.endswith("/"):
+        namelist = zf.namelist()
+        if len(namelist) > MAX_FILES:
+            return {"ok": False, "error": f"too many files in ZIP (max {MAX_FILES})"}
+
+        for info in zf.infolist():
+            if info.is_dir():
                 continue
-            data = zf.read(name)
+
+            # ZIP bomb: compression ratio check
+            if info.compress_size > 0:
+                ratio = info.file_size / info.compress_size
+                if ratio > MAX_RATIO:
+                    return {"ok": False, "error": f"suspicious compression ratio ({ratio:.0f}:1) — possible ZIP bomb"}
+
+            name = _sanitize_zip_name(info.filename)
+            if not name:
+                continue  # skip unsafe names
+
+            data = zf.read(info)
+            total_uncompressed += len(data)
+            if total_uncompressed > MAX_UNCOMPRESSED:
+                return {"ok": False, "error": f"uncompressed size exceeds {MAX_UNCOMPRESSED // 1024 // 1024}MB"}
+
             ext = name.rsplit(".", 1)[-1].lower() if "." in name else ""
             files.append({
                 "filename": name,