@@ -1022,6 +1022,19 @@ Debug options
 
    .. versionadded:: 3.6
 
+.. option:: --with-hwaddress-sanitizer
+
+   Enable HWAddressSanitizer memory error detector, ``hwasan`` (default is no).
+   Note that on x86-64 this uses `page aliasing
+   <https://clang.llvm.org/docs/HardwareAssistedAddressSanitizerDesign.html#supported-architectures>`_,
+   which only tags heap allocations and is unsafe for programs that ``fork()``,
+   including much of the test suite.
+   See the `LLVM HWASan design documentation
+   <https://clang.llvm.org/docs/HardwareAssistedAddressSanitizerDesign.html>`_
+   for more information.
+
+   .. versionadded:: next
+
 .. option:: --with-memory-sanitizer
 
    Enable MemorySanitizer allocation error detector, ``msan`` (default is no).

@@ -1171,6 +1171,11 @@ Build changes
 
   (Contributed by Stan Ulbrych in :gh:`139314`.)
 
+* Add the :option:`--with-hwaddress-sanitizer` :program:`configure` option to
+  build with `HWAddressSanitizer <https://clang.llvm.org/docs/HardwareAssistedAddressSanitizerDesign.html>`_.
+
+  (Contributed by Stan Ulbrych, Florian Mayer and AnnaAr321 in :gh:`156049`.)
+
 
 C API changes
 =============

diff --git a/Include/pyport.h b/Include/pyport.h
@@ -567,6 +567,12 @@ extern "C" {
 #      define _Py_NO_SANITIZE_ADDRESS __attribute__((no_sanitize_address))
 #    endif
 #  endif
+#  if __has_feature(hwaddress_sanitizer)
+#    if !defined(_Py_ADDRESS_SANITIZER)
+#      define _Py_ADDRESS_SANITIZER
+#      define _Py_NO_SANITIZE_ADDRESS __attribute__((no_sanitize("hwaddress")))
+#    endif
+#  endif
 #  if __has_feature(thread_sanitizer)
 #    if !defined(_Py_THREAD_SANITIZER)
 #      define _Py_THREAD_SANITIZER
@@ -577,6 +583,9 @@ extern "C" {
 #  if defined(__SANITIZE_ADDRESS__)
 #    define _Py_ADDRESS_SANITIZER
 #    define _Py_NO_SANITIZE_ADDRESS __attribute__((no_sanitize_address))
+#  elif defined(__SANITIZE_HWADDRESS__)
+#    define _Py_ADDRESS_SANITIZER
+#    define _Py_NO_SANITIZE_ADDRESS __attribute__((no_sanitize("hwaddress")))
 #  endif
 #  if defined(__SANITIZE_THREAD__)
 #    define _Py_THREAD_SANITIZER

diff --git a/Lib/test/libregrtest/utils.py b/Lib/test/libregrtest/utils.py
@@ -397,7 +397,9 @@ def get_build_info():
 
     # --with-address-sanitizer
     sanitizers = []
-    if support.check_sanitizer(address=True):
+    if support.check_sanitizer(hwaddress=True):
+        sanitizers.append("HWASAN")
+    elif support.check_sanitizer(address=True):
         sanitizers.append("ASAN")
     # --with-memory-sanitizer
     if support.check_sanitizer(memory=True):

diff --git a/Lib/test/support/__init__.py b/Lib/test/support/__init__.py
@@ -448,11 +448,12 @@ def skip_if_buildbot(reason=None):
         isbuildbot = False
     return unittest.skipIf(isbuildbot, reason)
 
-def check_sanitizer(*, address=False, memory=False, ub=False, thread=False,
-                    function=True):
+def check_sanitizer(*, address=False, hwaddress=False, memory=False, ub=False,
+                    thread=False, function=True):
     """Returns True if Python is compiled with sanitizer support"""
-    if not (address or memory or ub or thread):
-        raise ValueError('At least one of address, memory, ub or thread must be True')
+    if not (address or hwaddress or memory or ub or thread):
+        raise ValueError('At least one of address, hwaddress, memory, ub or '
+                         'thread must be True')
 
 
     cflags = sysconfig.get_config_var('CFLAGS') or ''
@@ -461,9 +462,14 @@ def check_sanitizer(*, address=False, memory=False, ub=False, thread=False,
         '-fsanitize=memory' in cflags or
         '--with-memory-sanitizer' in config_args
     )
+    hwaddress_sanitizer = (
+        '-fsanitize=hwaddress' in cflags or
+        '--with-hwaddress-sanitizer' in config_args
+    )
     address_sanitizer = (
         '-fsanitize=address' in cflags or
-        '--with-address-sanitizer' in config_args
+        '--with-address-sanitizer' in config_args or
+        hwaddress_sanitizer
     )
     ub_sanitizer = (
         '-fsanitize=undefined' in cflags or
@@ -479,6 +485,7 @@ def check_sanitizer(*, address=False, memory=False, ub=False, thread=False,
     return (
         (memory and memory_sanitizer) or
         (address and address_sanitizer) or
+        (hwaddress and hwaddress_sanitizer) or
         (ub and ub_sanitizer) or
         (thread and thread_sanitizer) or
         (function and function_sanitizer)

diff --git a/Lib/test/test_capi/test_mem.py b/Lib/test/test_capi/test_mem.py
@@ -182,5 +182,18 @@ class PyMemDefaultTests(PyMemDebugTests):
     PYTHONMALLOC = ''
 
 
+@requires_subprocess()
+@unittest.skipUnless(support.check_sanitizer(address=True),
+                     'need address sanitizer')
+class AddressSanitizerTests(unittest.TestCase):
+    def test_buffer_overflow(self):
+        with support.SuppressCrashReport():
+            out = assert_python_failure(
+                '-c', 'import _testcapi; _testcapi.pymem_buffer_overflow()',
+                PYTHONMALLOC='malloc',
+            )
+        self.assertIn(b'AddressSanitizer', out.err)
+
+
 if __name__ == "__main__":
     unittest.main()
diff --git a/Misc/NEWS.d/next/Build/2026-08-31-15-50-04.gh-issue-156049.FCf6hP.rst b/Misc/NEWS.d/next/Build/2026-08-31-15-50-04.gh-issue-156049.FCf6hP.rst
@@ -0,0 +1,2 @@
+Add :option:`--with-hwaddress-sanitizer` to build with `HWAddressSanitizer
+<https://clang.llvm.org/docs/HardwareAssistedAddressSanitizerDesign.html>`_.
@@ -3531,6 +3531,34 @@ with_pymalloc="no"
 ],
 [AC_MSG_RESULT([no])])
 
+AC_MSG_CHECKING([for --with-hwaddress-sanitizer])
+AC_ARG_WITH(
+  [hwaddress_sanitizer],
+  [AS_HELP_STRING(
+    [--with-hwaddress-sanitizer],
+    [enable HWAddressSanitizer memory error detector, 'hwasan' (default is no)]
+  )],
+[
+AC_MSG_RESULT([$withval])
+hwasan_flags="-fsanitize=hwaddress"
+# x86-64 lacks address tagging, so HWASan needs the page aliasing mode there.
+# See gh-156049 and
+# https://clang.llvm.org/docs/HardwareAssistedAddressSanitizerDesign.html#supported-architectures
+AS_CASE([$host_cpu],
+  [x86_64|amd64], [hwasan_flags="$hwasan_flags -fsanitize-hwaddress-experimental-aliasing"]
+)
+AX_CHECK_COMPILE_FLAG([$hwasan_flags],[
+BASECFLAGS="$hwasan_flags -fno-omit-frame-pointer $BASECFLAGS"
+LDFLAGS="$hwasan_flags $LDFLAGS"
+],[AC_MSG_ERROR([The selected compiler doesn't support hardware address sanitizer])])
+# HWASan works by controlling memory allocation, our own malloc interferes,
+# so disable it by default, but allow --with-pymalloc to override.
+if test -z "$with_pymalloc"; then
+  with_pymalloc="no"
+fi
+],
+[AC_MSG_RESULT([no])])
+
 AC_MSG_CHECKING([for --with-memory-sanitizer])
 AC_ARG_WITH(
   [memory_sanitizer],
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,2 @@
		Add :option:`--with-hwaddress-sanitizer` to build with `HWAddressSanitizer
		<https://clang.llvm.org/docs/HardwareAssistedAddressSanitizerDesign.html>`_.