diff --git a/sdk_container/src/third_party/portage-stable/dev-python/cython/Manifest b/sdk_container/src/third_party/portage-stable/dev-python/cython/Manifest
index 78e39a3ba5..780b68fddd 100644
--- a/sdk_container/src/third_party/portage-stable/dev-python/cython/Manifest
+++ b/sdk_container/src/third_party/portage-stable/dev-python/cython/Manifest
@@ -1,2 +1,2 @@
 DIST cython-3.0.12.tar.gz 2757617 BLAKE2B 064549e36e03424065eab081b60e2761d198490cfd4d7836ea236b833ada3962e6ed42ba1710b33418f8a31ac282cdc156ceb544ee21be80ee34b7a3d3f6c7fb SHA512 c4e85596eeea444fae983d32ce8731cc5d0d612d1f96b998db3aa7946e8be151a7ea62c6df163d875111e306c870656b82a8468dd873cacf84c7bd5671a39bc3
-DIST cython-3.1.0b1.tar.gz 3192916 BLAKE2B 13a8fa48319d9c4c8cc634d3cf5af599b867466d5de4cf3a24dd342b7812a392e854d9a6152309c6ef84a2925ebfa2257792d0f4e0c8fa36580d7138a663105a SHA512 ced9d57536d3bacd274b5edc4137d400a6182b4b7a89a28cf358f843dcbb0e0e7171fb0842441a81e1d2ac12acb6fd6a3df7018fe2a8708cb188a96cb184d799
+DIST cython-3.1.0rc1.tar.gz 3158411 BLAKE2B 44540e95b8b060956654a0d92fc4b8417088816a1e3f8fc17c8575a1cbd4b71a76cc69209d58c731281a310a9f6a7e2e711f88dc6855bc487d08056203cb04d8 SHA512 b0cefe1d4e248e6044af373088902475839ae06b5855b5b3bffdce5159a0f6e54802c24715a6f6e3242a250841c2ff1e56435b7ed3e304964af01a162f8a851a
diff --git a/sdk_container/src/third_party/portage-stable/dev-python/cython/cython-3.1.0_rc1-r1.ebuild b/sdk_container/src/third_party/portage-stable/dev-python/cython/cython-3.1.0_rc1-r1.ebuild
new file mode 100644
index 0000000000..561a1b8a07
--- /dev/null
+++ b/sdk_container/src/third_party/portage-stable/dev-python/cython/cython-3.1.0_rc1-r1.ebuild
@@ -0,0 +1,86 @@
+# Copyright 1999-2025 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=8
+
+DISTUTILS_EXT=1
+DISTUTILS_USE_PEP517=setuptools
+PYTHON_TESTED=( python3_{10..12} )
+PYTHON_COMPAT=( "${PYTHON_TESTED[@]}" pypy3 pypy3_11 python3_13{,t} )
+PYTHON_REQ_USE="threads(+)"
+
+inherit distutils-r1 multiprocessing pypi toolchain-funcs
+
+DESCRIPTION="A Python to C compiler"
+HOMEPAGE="
+	https://cython.org/
+	https://github.com/cython/cython/
+	https://pypi.org/project/Cython/
+"
+
+LICENSE="Apache-2.0"
+SLOT="0"
+KEYWORDS="~alpha ~amd64 ~arm ~arm64 ~hppa ~loong ~m68k ~mips ~ppc ~ppc64 ~riscv ~s390 ~sparc ~x86 ~amd64-linux ~x86-linux ~arm64-macos ~ppc-macos ~x64-macos ~x64-solaris"
+IUSE="test"
+RESTRICT="!test? ( test )"
+
+BDEPEND="
+	${RDEPEND}
+	test? (
+		$(python_gen_cond_dep '
+			<dev-python/numpy-2[${PYTHON_USEDEP}]
+		' "${PYTHON_TESTED[@]}")
+	)
+"
+
+PATCHES=(
+	"${FILESDIR}/${PN}-0.29.22-spawn-multiprocessing.patch"
+	"${FILESDIR}/${PN}-0.29.23-pythran-parallel-install.patch"
+	# https://github.com/cython/cython/commit/a0794ffb47c9f44be94b3cd8fe6c639766cbda26
+	"${FILESDIR}/${P}-rdma-core-hang.patch"
+)
+
+distutils_enable_sphinx docs \
+	dev-python/jinja2 \
+	dev-python/sphinx-issues \
+	dev-python/sphinx-tabs
+
+python_prepare_all() {
+	# Needs dev-python/pip and doesn't like 'externally-managed' (bug #927995)
+	rm tests/run/coverage_cmd_src_pkg_layout.srctree || die
+
+	distutils-r1_python_prepare_all
+}
+
+python_compile() {
+	# Python gets confused when it is in sys.path before build.
+	local -x PYTHONPATH=
+
+	distutils-r1_python_compile
+}
+
+python_test() {
+	if ! has "${EPYTHON/./_}" "${PYTHON_TESTED[@]}"; then
+		einfo "Skipping tests on ${EPYTHON} (xfail)"
+		return
+	fi
+
+	# Needed to avoid confusing cache tests
+	unset CYTHON_FORCE_REGEN
+
+	tc-export CC
+	# https://github.com/cython/cython/issues/1911
+	local -x CFLAGS="${CFLAGS} -fno-strict-overflow"
+	"${PYTHON}" runtests.py \
+		-vv \
+		-j "$(makeopts_jobs)" \
+		--work-dir "${BUILD_DIR}"/tests \
+		--no-examples \
+		--no-code-style \
+		|| die "Tests fail with ${EPYTHON}"
+}
+
+python_install_all() {
+	local DOCS=( CHANGES.rst README.rst ToDo.txt USAGE.txt )
+	distutils-r1_python_install_all
+}
diff --git a/sdk_container/src/third_party/portage-stable/dev-python/cython/cython-3.1.0_beta1-r1.ebuild b/sdk_container/src/third_party/portage-stable/dev-python/cython/cython-3.1.0_rc1.ebuild
similarity index 96%
rename from sdk_container/src/third_party/portage-stable/dev-python/cython/cython-3.1.0_beta1-r1.ebuild
rename to sdk_container/src/third_party/portage-stable/dev-python/cython/cython-3.1.0_rc1.ebuild
index 540e52b73a..58fa8c542b 100644
--- a/sdk_container/src/third_party/portage-stable/dev-python/cython/cython-3.1.0_beta1-r1.ebuild
+++ b/sdk_container/src/third_party/portage-stable/dev-python/cython/cython-3.1.0_rc1.ebuild
@@ -36,8 +36,6 @@ BDEPEND="
 PATCHES=(
 	"${FILESDIR}/${PN}-0.29.22-spawn-multiprocessing.patch"
 	"${FILESDIR}/${PN}-0.29.23-pythran-parallel-install.patch"
-	# https://github.com/cython/cython/pull/6782
-	"${FILESDIR}/${P}-pypy3.patch"
 )
 
 distutils_enable_sphinx docs \
diff --git a/sdk_container/src/third_party/portage-stable/dev-python/cython/files/cython-3.1.0_beta1-pypy3.patch b/sdk_container/src/third_party/portage-stable/dev-python/cython/files/cython-3.1.0_beta1-pypy3.patch
deleted file mode 100644
index 9884e1b84a..0000000000
--- a/sdk_container/src/third_party/portage-stable/dev-python/cython/files/cython-3.1.0_beta1-pypy3.patch
+++ /dev/null
@@ -1,36 +0,0 @@
-From c1e709dd260b7621f36737b585dac1fd45a7704c Mon Sep 17 00:00:00 2001
-From: da-woods <dw-git@d-woods.co.uk>
-Date: Sun, 6 Apr 2025 08:43:34 +0100
-Subject: [PATCH] Fix __Pyx_Owned_Py_None usage as actual function (GH-6782)
-
-In the tracing code, we are using it like a function (i.e. casting to void to mark it unused) so it has to be a function, not just a macro.
-
-Fixes https://github.com/cython/cython/issues/6781
----
- Cython/Utility/TypeConversion.c | 6 +++++-
- 1 file changed, 5 insertions(+), 1 deletion(-)
-
-diff --git a/Cython/Utility/TypeConversion.c b/Cython/Utility/TypeConversion.c
-index b86125699c7..e085fae8eb3 100644
---- a/Cython/Utility/TypeConversion.c
-+++ b/Cython/Utility/TypeConversion.c
-@@ -103,7 +103,7 @@ static CYTHON_INLINE PyObject *__Pyx_XNewRef(PyObject *obj) {
- #endif
- }
- 
--#define __Pyx_Owned_Py_None(b) __Pyx_NewRef(Py_None)
-+static CYTHON_INLINE PyObject *__Pyx_Owned_Py_None(int b);
- static CYTHON_INLINE PyObject * __Pyx_PyBool_FromLong(long b);
- static CYTHON_INLINE int __Pyx_PyObject_IsTrue(PyObject*);
- static CYTHON_INLINE int __Pyx_PyObject_IsTrueAndDecref(PyObject*);
-@@ -420,6 +420,10 @@ static CYTHON_INLINE Py_hash_t __Pyx_PyIndex_AsHash_t(PyObject* o) {
-   }
- }
- 
-+static CYTHON_INLINE PyObject *__Pyx_Owned_Py_None(int b) {
-+    CYTHON_UNUSED_VAR(b);
-+    return __Pyx_NewRef(Py_None);
-+}
- 
- static CYTHON_INLINE PyObject * __Pyx_PyBool_FromLong(long b) {
-   return b ? __Pyx_NewRef(Py_True) : __Pyx_NewRef(Py_False);
diff --git a/sdk_container/src/third_party/portage-stable/dev-python/cython/files/cython-3.1.0_rc1-rdma-core-hang.patch b/sdk_container/src/third_party/portage-stable/dev-python/cython/files/cython-3.1.0_rc1-rdma-core-hang.patch
new file mode 100644
index 0000000000..3561870b04
--- /dev/null
+++ b/sdk_container/src/third_party/portage-stable/dev-python/cython/files/cython-3.1.0_rc1-rdma-core-hang.patch
@@ -0,0 +1,54 @@
+From a0794ffb47c9f44be94b3cd8fe6c639766cbda26 Mon Sep 17 00:00:00 2001
+From: Stefan Behnel <stefan_ml@behnel.de>
+Date: Sun, 4 May 2025 21:48:27 +0200
+Subject: [PATCH] Prevent infinite loop in type inference when a variable is
+ named like the type of its value (e.g. list += []).
+
+Closes https://github.com/cython/cython/issues/6835
+---
+ Cython/Compiler/ExprNodes.py |  2 +-
+ tests/run/type_inference.pyx | 24 ++++++++++++++++++++++++
+ 2 files changed, 25 insertions(+), 1 deletion(-)
+
+diff --git a/Cython/Compiler/ExprNodes.py b/Cython/Compiler/ExprNodes.py
+index a0413ab8d62..b02154a0b30 100644
+--- a/Cython/Compiler/ExprNodes.py
++++ b/Cython/Compiler/ExprNodes.py
+@@ -2042,7 +2042,7 @@ def infer_type(self, env):
+                 return self.inferred_type
+             return py_object_type
+         elif (self.entry.type.is_extension_type or self.entry.type.is_builtin_type) and \
+-                self.name == self.entry.type.name:
++                not self.is_target and self.name == self.entry.type.name:
+             # Unfortunately the type attribute of type objects
+             # is used for the pointer to the type they represent.
+             return type_type
+diff --git a/tests/run/type_inference.pyx b/tests/run/type_inference.pyx
+index b746d05d9f3..226455dae0d 100644
+--- a/tests/run/type_inference.pyx
++++ b/tests/run/type_inference.pyx
+@@ -883,3 +886,24 @@ def test_builtin_max():
+             a = max(self.a, self.a)
+             assert typeof(a) == "Python object", typeof(a)
+     C().get_max()
++
++
++def variable_with_name_of_type():
++    """
++    >>> variable_with_name_of_type()
++    ([], 'abc')
++    """
++    # Names like 'list.append' refer to the type and must be inferred as such,
++    # but a simple variable called 'list' is not the same and used to break type inference.
++    # See https://github.com/cython/cython/issues/6835
++    rest_list = []
++    list = []  # note: same name as type of value
++    list += rest_list
++    assert typeof(list) == 'list object', typeof(list)
++
++    rest_str = "abc"
++    str = ""
++    str += rest_str
++    assert typeof(str) == 'str object', typeof(str)
++
++    return list, str