diff --git a/HISTORY.md b/HISTORY.md
index 583062a142..4d1c0cf535 100644
--- a/HISTORY.md
+++ b/HISTORY.md
@@ -1,6 +1,14 @@
 Release History
 ===============
 
+3.12.1 (2025-01-03)
+-------------------
+
+**Fixed**
+- Certificate validation may end up in error in highly concurrent environment using the experimental freethreaded build.
+  This was due to a racing condition in our "verify" caching logic (e.g. avoid creating duplicate ssl_context where one is sufficient).
+  The GIL prevented this issue.
+
 3.12.0 (2025-01-01)
 -------------------
 
diff --git a/src/niquests/__version__.py b/src/niquests/__version__.py
index 24d0084a0a..eedb41f38d 100644
--- a/src/niquests/__version__.py
+++ b/src/niquests/__version__.py
@@ -9,9 +9,9 @@
 __url__: str = "https://niquests.readthedocs.io"
 
 __version__: str
-__version__ = "3.12.0"
+__version__ = "3.12.1"
 
-__build__: int = 0x031200
+__build__: int = 0x031201
 __author__: str = "Kenneth Reitz"
 __author_email__: str = "me@kennethreitz.org"
 __license__: str = "Apache-2.0"
diff --git a/src/niquests/adapters.py b/src/niquests/adapters.py
index 711d071cbb..127797a134 100644
--- a/src/niquests/adapters.py
+++ b/src/niquests/adapters.py
@@ -565,13 +565,9 @@ def cert_verify(
             return
 
         need_reboot_conn: bool = False
-        verify_witness_bit: bool = (
-            hasattr(conn, "_niquests_verify") and conn._niquests_verify == verify
-        )
+        verify_witness_bit: bool = getattr(conn, "_niquests_verify", object()) == verify
 
         if not verify_witness_bit:
-            setattr(conn, "_niquests_verify", verify)
-
             if verify:
                 cert_loc: str | None = None
                 cert_data: str | None = wassima.generate_ca_bundle()
@@ -638,6 +634,7 @@ def cert_verify(
                 conn.ca_cert_dir = None
                 conn.ca_cert_data = None
 
+            setattr(conn, "_niquests_verify", verify)
         if cert:
             if not isinstance(cert, str):
                 if "-----BEGIN CERTIFICATE-----" in cert[0]:
@@ -1665,13 +1662,9 @@ def cert_verify(
             return False
 
         need_reboot_conn: bool = False
-        verify_witness_bit: bool = (
-            hasattr(conn, "_niquests_verify") and conn._niquests_verify == verify
-        )
+        verify_witness_bit: bool = getattr(conn, "_niquests_verify", object()) == verify
 
         if not verify_witness_bit:
-            setattr(conn, "_niquests_verify", verify)
-
             if verify:
                 cert_loc: str | None = None
                 cert_data: str | None = wassima.generate_ca_bundle()
@@ -1737,6 +1730,8 @@ def cert_verify(
                 conn.ca_cert_dir = None
                 conn.ca_cert_data = None
 
+            setattr(conn, "_niquests_verify", verify)
+
         if cert:
             if not isinstance(cert, str):
                 if "-----BEGIN CERTIFICATE-----" in cert[0]:
diff --git a/src/niquests/help.py b/src/niquests/help.py
index a262d2d823..75af6af029 100644
--- a/src/niquests/help.py
+++ b/src/niquests/help.py
@@ -58,6 +58,11 @@
     wsproto = None  # type: ignore
 
 
+_IS_GIL_DISABLED: bool = (
+    hasattr(sys, "_is_gil_enabled") and sys._is_gil_enabled() is False
+)
+
+
 def _implementation():
     """Return a dict with the Python implementation and version.
 
@@ -132,6 +137,7 @@ def info():
         "platform": platform_info,
         "implementation": implementation_info,
         "system_ssl": system_ssl_info,
+        "gil": not _IS_GIL_DISABLED,
         "urllib3.future": urllib3_info,
         "charset_normalizer": charset_normalizer_info,
         "idna": idna_info,
@@ -209,8 +215,8 @@ def main() -> None:
 
     if __legacy_urllib3_version__ is not None:
         warnings.warn(
-            "urllib3-future is installed alongside (legacy) urllib3. This may cause compatibility issues."
-            "Some (Requests) 3rd parties may be bound to urllib3, therefor the plugins may wrongfully invoke"
+            "urllib3-future is installed alongside (legacy) urllib3. This may cause compatibility issues. "
+            "Some (Requests) 3rd parties may be bound to urllib3, therefor the plugins may wrongfully invoke "
             "urllib3 (legacy) instead of urllib3-future. To remediate this, run "
             "`python -m pip uninstall -y urllib3 urllib3-future`, then run `python -m pip install urllib3-future`.",
             UserWarning,