diff --git a/dev-libs/protobuf/Manifest b/dev-libs/protobuf/Manifest
index 51e1216c7de97..a3c3097b426b3 100644
--- a/dev-libs/protobuf/Manifest
+++ b/dev-libs/protobuf/Manifest
@@ -1,5 +1,6 @@
 DIST protobuf-21.12.tar.gz 5141166 BLAKE2B 33500612d103afb817062486a741e8e5503f82c42c70054d47d1899e6bb79f3fdde2666cad5b8eff6e1bc539c3b0cdf9f2b125ce7e5d3a459a69e84d67ab535e SHA512 2dc8f552388438268d8b9f7a9e84c6abf1736be3d5031438c789c317410c9f4b5cedd25bf7da6d67b3ba32ca890869f9ddaab2284d6ac0e734a5b135ffbb1346
 DIST protobuf-25.6.tar.gz 5878040 BLAKE2B b82848406890460d9321e6736e413290e1b4a73dc5f2d3db17dd4419e7ddbb788b6cdb52c884c3e7f0c49c5a69ce31468dcc311d73efca06f94ec51577472fcc SHA512 f1920414bbaed0a882b73349e1cd9cdf87c0d9c99790d70ab8ef589161a8dcad92361daec67bf9bf8350f4181fa8514b50362f1495f082ba5805c4a2e70b6308
+DIST protobuf-25.9.tar.gz 5876049 BLAKE2B 8a248798f0d99cb26bd1201af382d77c01ca4152f46513fb9e17fac8cf487b2aecc38664a82441e1c0aefb3f16b4052539591d4e9b880832371894208d606fcd SHA512 4ff2063b1fb882d4e0ceb39ea40c1f86790564f58ea5f2b2c4452c4cf50b1fded643233b45ec17092ad94132aa4bd4981c916209ed73dba4fa19d11998ac8220
 DIST protobuf-28.0.tar.gz 9259114 BLAKE2B 328e09ebffb296d838557ea72a4fc4da8e0ad5f1edfccebcc8ee7c9e0e74d06e5e6dbad741fd89f6a4502c1cb246a973fd60c035ccdbf89700b7baff49e2a65e SHA512 8745f625ac781f3bbefe9494cbf570143d38aecc1521edef7a52ffb403b8be24df2c71f4f2410b5a5b78a0f3e8a38a7d19be2cf916b1b9125349d2da18262cd1
 DIST protobuf-29.5.tar.gz 9338935 BLAKE2B cfffcab9e240047c1759f8304b0c2f553bf73c7dc2cfcf101eb1fad3a0f90991e9aa998ca34c7c9534cd4209edf50691e17b75208ae726565505cdb2ab229a7f SHA512 3f3bc241c8babe5988678386d83ef2a75e202bb109f47d62b2ee7915c9b1c080590c2812f6635ba61c41e9570a0aeaa4789cdcba80c917c33ff52ba1817811bb
 DIST protobuf-30.2.tar.gz 9506934 BLAKE2B 3a7d6bfa38500b16b1ce52b244fd9448fe7be2933a77224a1423a67e3ae3155846c0974ee1b6c579f6050f60b7784ace21b149b3cbdff2ef1e6bf954acbb1b51 SHA512 555d1b18d175eeaf17f3879f124d33080f490367840d35b34bfc4e4a5b383bf6a1d09f1570acb6af9c53ac4940a14572d46423b6e3dd0c712e7802c986fb6be6
diff --git a/dev-libs/protobuf/protobuf-25.9.ebuild b/dev-libs/protobuf/protobuf-25.9.ebuild
new file mode 100644
index 0000000000000..e5bb4efa154f9
--- /dev/null
+++ b/dev-libs/protobuf/protobuf-25.9.ebuild
@@ -0,0 +1,172 @@
+# Copyright 2008-2026 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=8
+
+inherit cmake-multilib elisp-common multilib toolchain-funcs
+
+# NOTE from https://github.com/protocolbuffers/protobuf/blob/main/.gitmodules
+ABSEIL_BRANCH="lts_2023_08_02"
+
+ABSEIL_MIN_VER="${ABSEIL_BRANCH//lts_}"
+ABSEIL_MIN_VER="${ABSEIL_MIN_VER//_/}"
+
+if [[ "${PV}" == *9999 ]]; then
+	EGIT_REPO_URI="https://github.com/protocolbuffers/protobuf.git"
+	EGIT_SUBMODULES=( '-*' )
+	SLOT="0/9999"
+
+	inherit git-r3
+else
+	SRC_URI="https://github.com/protocolbuffers/protobuf/releases/download/v${PV}/${P}.tar.gz"
+	KEYWORDS="~alpha ~amd64 ~arm ~arm64 ~loong ~mips ~ppc ~ppc64 ~riscv ~s390 ~sparc ~x86 ~arm64-macos ~x64-macos"
+	SLOT="0/$(ver_cut 1-2).0"
+fi
+
+DESCRIPTION="Google's Protocol Buffers - Extensible mechanism for serializing structured data"
+HOMEPAGE="https://protobuf.dev/"
+
+LICENSE="BSD"
+IUSE="conformance debug emacs examples +libprotoc +protobuf +protoc test zlib"
+
+# Require protobuf for the time being
+REQUIRED_USE="
+	protobuf
+	protobuf? ( protoc )
+	examples? ( protobuf )
+	libprotoc? ( protobuf )
+"
+
+RESTRICT="!test? ( test )"
+
+BDEPEND="
+	emacs? ( app-editors/emacs:* )
+"
+
+COMMON_DEPEND="
+	>=dev-cpp/abseil-cpp-${ABSEIL_MIN_VER}:=[${MULTILIB_USEDEP}]
+	zlib? ( virtual/zlib:=[${MULTILIB_USEDEP}] )
+"
+
+DEPEND="
+	${COMMON_DEPEND}
+	conformance? ( dev-libs/jsoncpp[${MULTILIB_USEDEP}] )
+	test? (
+		|| (
+			dev-cpp/abseil-cpp[test-helpers(-)]
+			dev-cpp/abseil-cpp[test]
+		)
+		dev-cpp/gtest[${MULTILIB_USEDEP}]
+	)
+"
+RDEPEND="
+	${COMMON_DEPEND}
+	${BDEPEND}
+"
+
+PATCHES=(
+	"${FILESDIR}/${PN}-26.1-disable-32-bit-tests.patch"
+	"${FILESDIR}/${PN}-23.3-static_assert-failure.patch"
+	"${FILESDIR}/${PN}-27.4-findJsonCpp.patch"
+)
+
+DOCS=( CONTRIBUTORS.txt README.md )
+
+src_prepare() {
+	cmake_src_prepare
+
+	cp "${FILESDIR}/FindJsonCpp.cmake" "${S}/cmake" || die
+}
+
+multilib_src_configure() {
+	local mycmakeargs=(
+		-Dprotobuf_ABSL_PROVIDER="package"
+		-Dprotobuf_JSONCPP_PROVIDER="package"
+
+		-Dprotobuf_BUILD_CONFORMANCE="$(usex test "$(usex conformance)")"
+		-Dprotobuf_BUILD_LIBPROTOC="$(usex libprotoc)"
+		-Dprotobuf_BUILD_PROTOBUF_BINARIES="$(usex protobuf)"
+		-Dprotobuf_BUILD_PROTOC_BINARIES="$(usex protoc)"
+		-Dprotobuf_BUILD_SHARED_LIBS="yes"
+		-Dprotobuf_BUILD_TESTS="$(usex test)"
+
+		-Dprotobuf_DISABLE_RTTI="no"
+
+		-Dprotobuf_INSTALL="yes"
+		-Dprotobuf_TEST_XML_OUTDIR="$(usex test)"
+
+		-Dprotobuf_WITH_ZLIB="$(usex zlib)"
+		-Dprotobuf_VERBOSE="$(usex debug)"
+		-DCMAKE_MODULE_PATH="${S}/cmake"
+	)
+	if use protobuf ; then
+		if use examples ; then
+			mycmakeargs+=(
+				-Dprotobuf_BUILD_EXAMPLES="$(usex examples)"
+				-Dprotobuf_INSTALL_EXAMPLES="$(usex examples)"
+			)
+		fi
+	fi
+
+	use test && mycmakeargs+=( -Dprotobuf_USE_EXTERNAL_GTEST="yes" )
+
+	cmake_src_configure
+}
+
+src_compile() {
+	cmake-multilib_src_compile
+
+	if use emacs; then
+		elisp-compile editors/protobuf-mode.el
+	fi
+}
+
+src_test() {
+	local -x srcdir="${S}/src"
+
+	local -x TEST_TMPDIR="${T%/}/TEST_TMPDIR_${ABI}"
+	mkdir -m 777 "${TEST_TMPDIR}" || die
+
+	setup_test_env() {
+		ln -sr "${S}/src" "${BUILD_DIR}/include" || die
+	}
+
+	multilib_foreach_abi setup_test_env
+
+	cmake-multilib_src_test
+}
+
+multilib_src_install_all() {
+	find "${ED}" -name "*.la" -delete || die
+
+	if ! tc-is-cross-compiler && [[ ! -f "${ED}/usr/$(get_libdir)/libprotobuf$(get_libname "${SLOT#*/}")" ]]; then
+		eerror "No matching library found with SLOT variable, currently set: ${SLOT}\n" \
+			"Expected value: ${ED}/usr/$(get_libdir)/libprotobuf$(get_libname "${SLOT#*/}")"
+		die "Please update SLOT variable"
+	fi
+
+	insinto /usr/share/vim/vimfiles/syntax
+	doins editors/proto.vim
+	insinto /usr/share/vim/vimfiles/ftdetect
+	doins "${FILESDIR}/proto.vim"
+
+	if use emacs; then
+		elisp-install "${PN}" editors/protobuf-mode.el*
+		elisp-site-file-install "${FILESDIR}/70${PN}-gentoo.el"
+	fi
+
+	if use examples; then
+		DOCS+=(examples)
+		docompress -x "/usr/share/doc/${PF}/examples"
+	fi
+
+	einstalldocs
+}
+
+pkg_postinst() {
+	use emacs && elisp-site-regen
+}
+
+pkg_postrm() {
+	use emacs && elisp-site-regen
+}