diff --git a/agent_assembly/cli/adapter_validator.py b/agent_assembly/cli/adapter_validator.py
index 3ca11747..0611a464 100644
--- a/agent_assembly/cli/adapter_validator.py
+++ b/agent_assembly/cli/adapter_validator.py
@@ -173,11 +173,27 @@ def _check_unregister_hooks_idempotent(
 
 def _check_entry_point_metadata(cls: type, path_or_module: str) -> AdapterValidationResult:
     """Check entry point metadata in pyproject.toml if present at the given path."""
-    search_path = Path(path_or_module)
+    # Canonicalize the CLI-supplied path before any file access. resolve()
+    # collapses ".." segments and symlinks, breaking path-traversal taint flows
+    # (pythonsecurity:S8707): the validator only inspects the pyproject.toml that
+    # sits directly inside the resolved adapter directory, never one reached by
+    # escaping it.
+    search_path = Path(path_or_module).resolve()
     if search_path.is_file():
         search_path = search_path.parent
 
-    pyproject_path = search_path / "pyproject.toml"
+    pyproject_path = (search_path / "pyproject.toml").resolve()
+
+    # Containment guard: the resolved manifest must live directly under the
+    # resolved adapter directory. A symlinked pyproject.toml pointing outside the
+    # adapter root is rejected rather than read.
+    if pyproject_path.parent != search_path:
+        return AdapterValidationResult(
+            check_name="entry_point_metadata",
+            passed=False,
+            message="pyproject.toml resolves outside the adapter directory; refusing to read it.",
+        )
+
     if not pyproject_path.is_file():
         return AdapterValidationResult(
             check_name="entry_point_metadata",
diff --git a/test/unit/cli/test_adapter_validator.py b/test/unit/cli/test_adapter_validator.py
index ecb596f5..8a22bc17 100644
--- a/test/unit/cli/test_adapter_validator.py
+++ b/test/unit/cli/test_adapter_validator.py
@@ -184,6 +184,45 @@ def test_no_pyproject_skips(self, valid_adapter_cls: type, tmp_path: object) ->
         assert result.passed is True
         assert "skipping" in result.message.lower()
 
+    def test_traversal_path_resolved_to_valid_dir(self, valid_adapter_cls: type, tmp_path: object) -> None:
+        """A path containing '..' that resolves to a real adapter dir still validates."""
+        import pathlib
+
+        assert isinstance(tmp_path, pathlib.Path)
+        adapter_dir = tmp_path / "adapter"
+        adapter_dir.mkdir()
+        pyproject = adapter_dir / "pyproject.toml"
+        qualname = f"{valid_adapter_cls.__module__}:{valid_adapter_cls.__qualname__}"
+        pyproject.write_text(f'[project.entry-points."agent_assembly.adapters"]\n' f'test_framework = "{qualname}"\n')
+        # "<tmp>/adapter/../adapter" canonicalizes back to "<tmp>/adapter".
+        traversal = str(adapter_dir / ".." / "adapter")
+        result = _check_entry_point_metadata(valid_adapter_cls, traversal)
+        assert result.passed is True
+
+    def test_symlinked_pyproject_outside_dir_rejected(self, valid_adapter_cls: type, tmp_path: object) -> None:
+        """A pyproject.toml symlink escaping the adapter dir is refused, not read."""
+        import pathlib
+
+        assert isinstance(tmp_path, pathlib.Path)
+        outside = tmp_path / "outside"
+        outside.mkdir()
+        secret = outside / "pyproject.toml"
+        secret.write_text("[project]\nname = 'secret'\n")
+
+        adapter_dir = tmp_path / "adapter"
+        adapter_dir.mkdir()
+        link = adapter_dir / "pyproject.toml"
+        try:
+            link.symlink_to(secret)
+        except (OSError, NotImplementedError):
+            import pytest
+
+            pytest.skip("platform does not support symlinks")
+
+        result = _check_entry_point_metadata(valid_adapter_cls, str(adapter_dir))
+        assert result.passed is False
+        assert "outside the adapter directory" in result.message
+
 
 class TestValidateAdapter:
     """Tests for validate_adapter orchestrator."""