diff --git a/backend/routers/mesh_oracle.py b/backend/routers/mesh_oracle.py
index 7e8cca6..35e024f 100644
--- a/backend/routers/mesh_oracle.py
+++ b/backend/routers/mesh_oracle.py
@@ -223,11 +223,21 @@ async def oracle_markets_more(request: Request, category: str = "NEWS", offset:
             "has_more": offset + limit < len(cat_markets), "total": len(cat_markets)}
 
 
-@router.post("/api/mesh/oracle/resolve")
+@router.post(
+    "/api/mesh/oracle/resolve",
+    dependencies=[Depends(require_admin)],
+)
 @limiter.limit("5/minute")
 @mesh_write_exempt(MeshWriteExemption.ADMIN_CONTROL)
 async def oracle_resolve(request: Request):
-    """Resolve a prediction market."""
+    """Resolve a prediction market.
+
+    Issue #240 (tg12): requires admin authentication. The
+    ``mesh_write_exempt`` decorator below is **metadata only** — it tags
+    the route as not requiring a mesh signed-write envelope, it does
+    NOT itself enforce caller authorization. The ``Depends(require_admin)``
+    on the route decorator is what actually gates access.
+    """
     from services.mesh.mesh_oracle import oracle_ledger
     body = await request.json()
     market_title = body.get("market_title", "")
@@ -327,11 +337,18 @@ async def oracle_predictions(request: Request, node_id: str = ""):
         active_predictions, authenticated=_scoped_view_authenticated(request, "mesh.audit"))
 
 
-@router.post("/api/mesh/oracle/resolve-stakes")
+@router.post(
+    "/api/mesh/oracle/resolve-stakes",
+    dependencies=[Depends(require_admin)],
+)
 @limiter.limit("5/minute")
 @mesh_write_exempt(MeshWriteExemption.ADMIN_CONTROL)
 async def oracle_resolve_stakes(request: Request):
-    """Resolve all expired stake contests."""
+    """Resolve all expired stake contests.
+
+    Issue #241 (tg12): requires admin authentication. See the note on
+    ``oracle_resolve`` above — ``mesh_write_exempt`` is metadata only.
+    """
     from services.mesh.mesh_oracle import oracle_ledger
     resolutions = oracle_ledger.resolve_expired_stakes()
     return {"ok": True, "resolutions": resolutions, "count": len(resolutions)}
diff --git a/backend/tests/test_oracle_resolve_auth_gate.py b/backend/tests/test_oracle_resolve_auth_gate.py
new file mode 100644
index 0000000..d89fb72
--- /dev/null
+++ b/backend/tests/test_oracle_resolve_auth_gate.py
@@ -0,0 +1,160 @@
+"""Issues #240 & #241 (tg12): oracle market/stake resolution endpoints
+must require admin authentication.
+
+Before the fix, ``POST /api/mesh/oracle/resolve`` and
+``POST /api/mesh/oracle/resolve-stakes`` were decorated with
+``@mesh_write_exempt(MeshWriteExemption.ADMIN_CONTROL)``. That decorator
+only tags the route as not requiring a mesh signed-write envelope; it
+does NOT enforce authorization. The rate limiter (5/minute) was the
+only real gate, which is wrong for control-plane state mutations.
+
+The fix adds ``dependencies=[Depends(require_admin)]`` to both routes.
+These tests prove:
+
+- Anonymous callers receive 403.
+- A request bearing the configured admin key passes the auth gate.
+- The underlying ledger mutator is not invoked on a 403.
+"""
+from __future__ import annotations
+
+from unittest.mock import patch, MagicMock
+
+import pytest
+from fastapi.testclient import TestClient
+
+
+_ADMIN_KEY = "test-admin-key-for-oracle-resolve-fixture-32+"
+
+
+@pytest.fixture
+def client():
+    """TestClient with the private-lane transport middleware short-circuited.
+
+    The ``enforce_high_privacy_mesh`` middleware in ``main.py`` returns
+    HTTP 202 ("preparing private lane") for ``/api/mesh/*`` requests
+    when the Wormhole supervisor is not yet at the required transport
+    tier. In tests that's always — Wormhole is not running. Patching
+    ``_minimum_transport_tier`` to return None disables the tier check
+    for the duration of the test, letting the request reach the route
+    (and therefore reach the ``Depends(require_admin)`` we are testing).
+    """
+    import main
+    with patch("main._minimum_transport_tier", return_value=None):
+        yield TestClient(main.app, raise_server_exceptions=False)
+
+
+@pytest.fixture
+def mock_ledger():
+    """Replace oracle_ledger methods so tests don't mutate persistent state.
+
+    The handler does ``from services.mesh.mesh_oracle import oracle_ledger``
+    at call time, so we patch the module attribute.
+    """
+    fake = MagicMock()
+    fake.resolve_market.return_value = (0, 0)
+    fake.resolve_market_stakes.return_value = {"winners": 0, "losers": 0}
+    fake.resolve_expired_stakes.return_value = []
+    with patch("services.mesh.mesh_oracle.oracle_ledger", fake):
+        yield fake
+
+
+# ---------------------------------------------------------------------------
+# /api/mesh/oracle/resolve — issue #240
+# ---------------------------------------------------------------------------
+
+
+class TestOracleResolveAuthGate:
+    def test_anonymous_caller_is_rejected(self, client, mock_ledger):
+        with patch("auth._current_admin_key", return_value=_ADMIN_KEY):
+            r = client.post(
+                "/api/mesh/oracle/resolve",
+                json={"market_title": "test-market", "outcome": "Yes"},
+            )
+        assert r.status_code == 403
+        # Critically: the ledger mutator must NOT have been called on a 403.
+        assert mock_ledger.resolve_market.call_count == 0
+        assert mock_ledger.resolve_market_stakes.call_count == 0
+
+    def test_wrong_admin_key_rejected(self, client, mock_ledger):
+        with patch("auth._current_admin_key", return_value=_ADMIN_KEY):
+            r = client.post(
+                "/api/mesh/oracle/resolve",
+                headers={"X-Admin-Key": "this-key-is-wrong"},
+                json={"market_title": "test-market", "outcome": "Yes"},
+            )
+        assert r.status_code == 403
+        assert mock_ledger.resolve_market.call_count == 0
+
+    def test_valid_admin_key_passes_auth_gate(self, client, mock_ledger):
+        with patch("auth._current_admin_key", return_value=_ADMIN_KEY):
+            r = client.post(
+                "/api/mesh/oracle/resolve",
+                headers={"X-Admin-Key": _ADMIN_KEY},
+                json={"market_title": "test-market", "outcome": "Yes"},
+            )
+        # The auth gate let us through. The handler ran and called the
+        # (mocked) ledger.
+        assert r.status_code == 200
+        assert mock_ledger.resolve_market.call_count == 1
+        assert mock_ledger.resolve_market.call_args[0] == ("test-market", "Yes")
+
+    def test_admin_key_unset_blocks_in_production_posture(self, client, mock_ledger):
+        """When ADMIN_KEY env is not configured at all and we're not in
+        debug, the endpoint must still refuse — never silently accept."""
+        with (
+            patch("auth._current_admin_key", return_value=""),
+            patch("auth._allow_insecure_admin", return_value=False),
+            patch("auth._debug_mode_enabled", return_value=False),
+            patch("auth._scoped_admin_tokens", return_value={}),
+        ):
+            r = client.post(
+                "/api/mesh/oracle/resolve",
+                json={"market_title": "test-market", "outcome": "Yes"},
+            )
+        assert r.status_code == 403
+        assert mock_ledger.resolve_market.call_count == 0
+
+
+# ---------------------------------------------------------------------------
+# /api/mesh/oracle/resolve-stakes — issue #241
+# ---------------------------------------------------------------------------
+
+
+class TestOracleResolveStakesAuthGate:
+    def test_anonymous_caller_is_rejected(self, client, mock_ledger):
+        with patch("auth._current_admin_key", return_value=_ADMIN_KEY):
+            r = client.post("/api/mesh/oracle/resolve-stakes")
+        assert r.status_code == 403
+        assert mock_ledger.resolve_expired_stakes.call_count == 0
+
+    def test_wrong_admin_key_rejected(self, client, mock_ledger):
+        with patch("auth._current_admin_key", return_value=_ADMIN_KEY):
+            r = client.post(
+                "/api/mesh/oracle/resolve-stakes",
+                headers={"X-Admin-Key": "nope"},
+            )
+        assert r.status_code == 403
+        assert mock_ledger.resolve_expired_stakes.call_count == 0
+
+    def test_valid_admin_key_passes_auth_gate(self, client, mock_ledger):
+        with patch("auth._current_admin_key", return_value=_ADMIN_KEY):
+            r = client.post(
+                "/api/mesh/oracle/resolve-stakes",
+                headers={"X-Admin-Key": _ADMIN_KEY},
+            )
+        assert r.status_code == 200
+        assert mock_ledger.resolve_expired_stakes.call_count == 1
+        body = r.json()
+        assert body["ok"] is True
+        assert body["count"] == 0
+
+    def test_admin_key_unset_blocks_in_production_posture(self, client, mock_ledger):
+        with (
+            patch("auth._current_admin_key", return_value=""),
+            patch("auth._allow_insecure_admin", return_value=False),
+            patch("auth._debug_mode_enabled", return_value=False),
+            patch("auth._scoped_admin_tokens", return_value={}),
+        ):
+            r = client.post("/api/mesh/oracle/resolve-stakes")
+        assert r.status_code == 403
+        assert mock_ledger.resolve_expired_stakes.call_count == 0