diff --git a/cumulusci/utils/__init__.py b/cumulusci/utils/__init__.py
index 7d68f2cd35..ae09c7766a 100644
--- a/cumulusci/utils/__init__.py
+++ b/cumulusci/utils/__init__.py
@@ -16,6 +16,14 @@
 import requests
 import sarge
 
+if not hasattr(sarge.Capture, "flush"):
+    # sarge==0.1.7.post1 ships Capture without flush(); on Python 3.13+ the
+    # interpreter-shutdown logging path calls flush() on captured streams and
+    # surfaces a cosmetic AttributeError after refresh_oauth_token. Upstream
+    # has the fix on master but no release. Defensive, idempotent shim.
+    # See SFDO-Tooling/CumulusCI#3852.
+    sarge.Capture.flush = lambda self: None
+
 from cumulusci.core.exceptions import CumulusCIException
 from .xml import (  # noqa
     elementtree_parse_file,
diff --git a/cumulusci/utils/tests/test_sarge_patch.py b/cumulusci/utils/tests/test_sarge_patch.py
new file mode 100644
index 0000000000..5e83e2dc06
--- /dev/null
+++ b/cumulusci/utils/tests/test_sarge_patch.py
@@ -0,0 +1,34 @@
+"""Regression test for SFDO-Tooling/CumulusCI#3852.
+
+``sarge==0.1.7.post1`` (the version pinned via ``pyproject.toml``) ships a
+``sarge.Capture`` class with no ``flush()`` method. On Python 3.13+ the
+interpreter-shutdown logging path calls ``.flush()`` on the captured stream
+objects CumulusCI hands to logging handlers, which surfaces a cosmetic
+``AttributeError: 'Capture' object has no attribute 'flush'`` after
+``refresh_oauth_token`` runs.
+
+The upstream sarge fix (``def flush(self): pass``) is unreleased, so
+``cumulusci.utils`` installs a defensive shim at import time. This test
+guards that shim.
+"""
+
+import sarge
+
+import cumulusci.utils  # noqa: F401 -- importing applies the Capture.flush shim
+
+
+def test_sarge_capture_has_flush_after_importing_cumulusci_utils():
+    assert hasattr(sarge.Capture, "flush"), (
+        "sarge.Capture is missing flush(); CumulusCI must patch it to avoid "
+        "AttributeError during interpreter-shutdown logging on Python 3.13+ "
+        "(see SFDO-Tooling/CumulusCI#3852)."
+    )
+    assert callable(sarge.Capture.flush)
+
+
+def test_sarge_capture_instance_flush_is_a_no_op():
+    capture = sarge.Capture()
+    try:
+        assert capture.flush() is None
+    finally:
+        capture.close()