diff --git a/tests/conftest.py b/tests/conftest.py
index 976b48ccc..69403937c 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -166,3 +166,33 @@ def _manage_distributed_env(request: FixtureRequest, monkeypatch: MonkeyPatch) -
 def fix_valuehead_cpu_loading():
     """Fix valuehead model loading."""
     patch_valuehead_model()
+
+
+@pytest.fixture(scope="session", autouse=True)
+def bypass_mistral_regex_check():
+    """Disable Mistral regex network check.
+
+    Monkey-patch TokenizersBackend._patch_mistral_regex into a no-op.
+    """
+    try:
+        from transformers.tokenization_utils_fast import TokenizersBackend
+    except ImportError:
+        # Very old transformers, nothing to patch
+        yield
+        return
+
+    if not hasattr(TokenizersBackend, "_patch_mistral_regex"):
+        # Method does not exist in this version
+        yield
+        return
+
+    # Backup original method
+    original = TokenizersBackend._patch_mistral_regex
+
+    # Replace with no-op
+    TokenizersBackend._patch_mistral_regex = lambda cls, tokenizer, *args, **kwargs: tokenizer
+
+    yield
+
+    # Restore original method
+    TokenizersBackend._patch_mistral_regex = original
diff --git a/tests_v1/conftest.py b/tests_v1/conftest.py
index adb08d49f..34797227a 100644
--- a/tests_v1/conftest.py
+++ b/tests_v1/conftest.py
@@ -172,3 +172,33 @@ def _manage_distributed_env(request: FixtureRequest, monkeypatch: MonkeyPatch) -
             monkeypatch.setattr(torch.cuda, "device_count", lambda: 1)
         elif CURRENT_DEVICE == "npu":
             monkeypatch.setattr(torch.npu, "device_count", lambda: 1)
+
+
+@pytest.fixture(scope="session", autouse=True)
+def bypass_mistral_regex_check():
+    """Disable Mistral regex network check.
+
+    Monkey-patch TokenizersBackend._patch_mistral_regex into a no-op.
+    """
+    try:
+        from transformers.tokenization_utils_fast import TokenizersBackend
+    except ImportError:
+        # Very old transformers, nothing to patch
+        yield
+        return
+
+    if not hasattr(TokenizersBackend, "_patch_mistral_regex"):
+        # Method does not exist in this version
+        yield
+        return
+
+    # Backup original method
+    original = TokenizersBackend._patch_mistral_regex
+
+    # Replace with no-op
+    TokenizersBackend._patch_mistral_regex = lambda cls, tokenizer, *args, **kwargs: tokenizer
+
+    yield
+
+    # Restore original method
+    TokenizersBackend._patch_mistral_regex = original