diff --git a/Lib/test/test_capi/test_opt.py b/Lib/test/test_capi/test_opt.py
index 58242f9ac3a01f..51234a2e40f54f 100644
--- a/Lib/test/test_capi/test_opt.py
+++ b/Lib/test/test_capi/test_opt.py
@@ -2662,6 +2662,38 @@ def f():
                               f" {executor} at offset {idx} rather"
                               f" than expected _EXIT_TRACE")
 
+    def test_enter_executor_valid_op_arg(self):
+        script_helper.assert_python_ok("-c", textwrap.dedent("""
+            import sys
+            sys.setrecursionlimit(30) # reduce time of the run
+
+            str_v1 = ''
+            tuple_v2 = (None, None, None, None, None)
+            small_int_v3 = 4
+
+            def f1():
+
+                for _ in range(10):
+                    abs(0)
+
+                tuple_v2[small_int_v3]
+                tuple_v2[small_int_v3]
+                tuple_v2[small_int_v3]
+
+                def recursive_wrapper_4569():
+                    str_v1 > str_v1
+                    str_v1 > str_v1
+                    str_v1 > str_v1
+                    recursive_wrapper_4569()
+
+                recursive_wrapper_4569()
+
+            for i_f1 in range(19000):
+                try:
+                    f1()
+                except RecursionError:
+                    pass
+        """))
 
 
 def global_identity(x):
diff --git a/Lib/test/test_hashlib.py b/Lib/test/test_hashlib.py
index 33845d8a9e2651..489bb049d2fadb 100644
--- a/Lib/test/test_hashlib.py
+++ b/Lib/test/test_hashlib.py
@@ -40,12 +40,15 @@
 openssl_hashlib = import_fresh_module('hashlib', fresh=['_hashlib'])
 
 try:
-    from _hashlib import HASH, HASHXOF, openssl_md_meth_names, get_fips_mode
+    import _hashlib
 except ImportError:
-    HASH = None
-    HASHXOF = None
-    openssl_md_meth_names = frozenset()
-
+    _hashlib = None
+# The extension module may exist but only define some of these. gh-141907
+HASH = getattr(_hashlib, 'HASH', None)
+HASHXOF = getattr(_hashlib, 'HASHXOF', None)
+openssl_md_meth_names = getattr(_hashlib, 'openssl_md_meth_names', frozenset())
+get_fips_mode = getattr(_hashlib, 'get_fips_mode', None)
+if not get_fips_mode:
     def get_fips_mode():
         return 0
 
@@ -631,9 +634,14 @@ def check_sha3(self, name, capacity, rate, suffix):
         constructors = self.constructors_to_test[name]
         for hash_object_constructor in constructors:
             m = hash_object_constructor()
-            if HASH is not None and isinstance(m, HASH):
-                # _hashopenssl's variant does not have extra SHA3 attributes
-                continue
+            if name.startswith('shake_'):
+                if HASHXOF is not None and isinstance(m, HASHXOF):
+                    # _hashopenssl's variant does not have extra SHA3 attributes
+                    continue
+            else:
+                if HASH is not None and isinstance(m, HASH):
+                    # _hashopenssl's variant does not have extra SHA3 attributes
+                    continue
             self.assertEqual(capacity + rate, 1600)
             self.assertEqual(m._capacity_bits, capacity)
             self.assertEqual(m._rate_bits, rate)
@@ -1156,7 +1164,8 @@ def test_disallow_instantiation(self):
     def test_hash_disallow_instantiation(self):
         # internal types like _hashlib.HASH are not constructable
         support.check_disallow_instantiation(self, HASH)
-        support.check_disallow_instantiation(self, HASHXOF)
+        if HASHXOF is not None:
+            support.check_disallow_instantiation(self, HASHXOF)
 
     def test_readonly_types(self):
         for algorithm, constructors in self.constructors_to_test.items():
diff --git a/Lib/test/test_monitoring.py b/Lib/test/test_monitoring.py
index 9b940740ca1bf9..83bf510ceea18c 100644
--- a/Lib/test/test_monitoring.py
+++ b/Lib/test/test_monitoring.py
@@ -12,10 +12,10 @@
 import unittest
 
 import test.support
-from test.support import requires_specialization_ft, script_helper
+from test.support import import_helper, requires_specialization_ft, script_helper
 
-_testcapi = test.support.import_helper.import_module("_testcapi")
-_testinternalcapi = test.support.import_helper.import_module("_testinternalcapi")
+_testcapi = import_helper.import_module("_testcapi")
+_testinternalcapi = import_helper.import_module("_testinternalcapi")
 
 PAIR = (0,1)
 
diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2025-11-25-02-23-31.gh-issue-141861.QcMdcM.rst b/Misc/NEWS.d/next/Core_and_Builtins/2025-11-25-02-23-31.gh-issue-141861.QcMdcM.rst
new file mode 100644
index 00000000000000..4a115669998975
--- /dev/null
+++ b/Misc/NEWS.d/next/Core_and_Builtins/2025-11-25-02-23-31.gh-issue-141861.QcMdcM.rst
@@ -0,0 +1 @@
+Fix invalid memory read in the ``ENTER_EXECUTOR`` instruction.
diff --git a/Python/bytecodes.c b/Python/bytecodes.c
index 12ee506e4f2bc4..6129ea2e723273 100644
--- a/Python/bytecodes.c
+++ b/Python/bytecodes.c
@@ -3018,7 +3018,7 @@ dummy_func(
                 goto stop_tracing;
             }
             PyCodeObject *code = _PyFrame_GetCode(frame);
-            _PyExecutorObject *executor = code->co_executors->executors[oparg & 255];
+            _PyExecutorObject *executor = code->co_executors->executors[this_instr->op.arg];
             assert(executor->vm_data.index == INSTR_OFFSET() - 1);
             assert(executor->vm_data.code == code);
             assert(executor->vm_data.valid);
diff --git a/Python/generated_cases.c.h b/Python/generated_cases.c.h
index b83b7c528e9150..47805c270f9a0e 100644
--- a/Python/generated_cases.c.h
+++ b/Python/generated_cases.c.h
@@ -5476,7 +5476,7 @@
                 JUMP_TO_LABEL(stop_tracing);
             }
             PyCodeObject *code = _PyFrame_GetCode(frame);
-            _PyExecutorObject *executor = code->co_executors->executors[oparg & 255];
+            _PyExecutorObject *executor = code->co_executors->executors[this_instr->op.arg];
             assert(executor->vm_data.index == INSTR_OFFSET() - 1);
             assert(executor->vm_data.code == code);
             assert(executor->vm_data.valid);