diff --git a/src/specify_cli/bundler/services/packager.py b/src/specify_cli/bundler/services/packager.py
index 4e14934e0a..591beb348d 100644
--- a/src/specify_cli/bundler/services/packager.py
+++ b/src/specify_cli/bundler/services/packager.py
@@ -14,6 +14,7 @@
 from pathlib import Path
 
 from .. import BundlerError
+from ..._download_security import MAX_ZIP_MEMBER_BYTES
 from ..lib.yamlio import ensure_within
 from ..models.manifest import BundleManifest
 from .validator import validate_manifest
@@ -97,7 +98,20 @@ def build_bundle(
                 st = os.fstat(fh.fileno())
                 mode = 0o755 if st.st_mode & 0o111 else 0o644
                 info.external_attr = mode << 16
-                archive.writestr(info, fh.read())
+                # Fast metadata rejection: skip files whose size exceeds the
+                # limit before touching the read path.  Then also bound the
+                # actual read so a TOCTOU race (file appended after fstat)
+                # cannot bypass the limit.
+                if st.st_size > MAX_ZIP_MEMBER_BYTES:
+                    raise BundlerError(
+                        f"Bundle file {arcname} exceeds {MAX_ZIP_MEMBER_BYTES}-byte limit"
+                    )
+                content = fh.read(MAX_ZIP_MEMBER_BYTES + 1)
+                if len(content) > MAX_ZIP_MEMBER_BYTES:
+                    raise BundlerError(
+                        f"Bundle file {arcname} exceeds {MAX_ZIP_MEMBER_BYTES}-byte limit"
+                    )
+                archive.writestr(info, content)
 
     return BuildResult(artifact_path=artifact_path, file_count=len(files))
 
diff --git a/tests/unit/test_bundler_packager.py b/tests/unit/test_bundler_packager.py
index d203f7ffb0..4ea938432a 100644
--- a/tests/unit/test_bundler_packager.py
+++ b/tests/unit/test_bundler_packager.py
@@ -10,6 +10,7 @@
 
 from specify_cli.bundler import BundlerError
 from specify_cli.bundler.services.packager import build_bundle
+from specify_cli._download_security import MAX_ZIP_MEMBER_BYTES
 from tests.bundler_helpers import valid_manifest_dict
 
 
@@ -234,3 +235,28 @@ def test_toctou_stat_read_consistency(tmp_path: Path):
     assert content == b"\x00\x01\x02\x03"
     assert modes["assets/data.bin"] == 0o644
     assert modes["README.md"] == 0o644
+
+
+def test_oversized_asset_file_is_rejected(tmp_path: Path):
+    """A single file exceeding MAX_ZIP_MEMBER_BYTES must be refused, not read
+    into memory unbounded."""
+    bundle = _make_bundle(tmp_path / "b")
+    oversized = bundle / "assets" / "huge.bin"
+    oversized.parent.mkdir(parents=True, exist_ok=True)
+    oversized.write_bytes(b"\x00" * (MAX_ZIP_MEMBER_BYTES + 1))
+
+    with pytest.raises(BundlerError, match="exceeds.*byte limit"):
+        build_bundle(bundle, output_dir=tmp_path / "out")
+
+
+def test_asset_at_exact_size_limit_is_accepted(tmp_path: Path):
+    """A file exactly at MAX_ZIP_MEMBER_BYTES must still be packaged."""
+    bundle = _make_bundle(tmp_path / "b")
+    at_limit = bundle / "assets" / "exact.bin"
+    at_limit.parent.mkdir(parents=True, exist_ok=True)
+    at_limit.write_bytes(b"\x00" * MAX_ZIP_MEMBER_BYTES)
+
+    result = build_bundle(bundle, output_dir=tmp_path / "out")
+    with zipfile.ZipFile(result.artifact_path) as archive:
+        content = archive.read("assets/exact.bin")
+    assert len(content) == MAX_ZIP_MEMBER_BYTES