From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9CD793DAABE for ; Mon, 27 Jul 2026 06:32:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785133974; cv=none; b=UZmum/k+BmvNwSLSTyKKcrFPRu6u7TFK/UQJbo5SWTDs/yyne1RAf9S9iPSuuLfPazaEguN7wfRxKaLgE34EW6kXmjmnQktIHDUNSZXrqKREgXPYR4AwIXhWp8v7dynzyE0PjS8o4CIx9jmRT3NcaEOsIoYCiMN/2dEI9BbpNOA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785133974; c=relaxed/simple; bh=ia1F4deBoFTw95XU7fSUuWYtxAyruLJgXgeHdHsh/0c=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=NKSypLnnaCy/7bkc0iPhT2OSfDvbmKaotSa0uO2sZObFW083SaUp8rkouOeiMRm5g8ebQ8wqgJuAlwQ4ww/85riK69sLmb8rF7RySCOzMgHliSQsgP+ODFktAdVImdTZYT4jzqOhoS6onxMCOa8Oe/7EWI+eqmLw23dxI7O3CXs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Wz0c9LJv; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="Wz0c9LJv" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6BCE81F000E9; Mon, 27 Jul 2026 06:32:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1785133970; bh=D2x1eZiiEogJQuAugPEXfKpV5jyOMMf8zV4Lnnk+sK8=; h=From:To:Cc:Subject:Date:Reply-To; b=Wz0c9LJvMuH7t1xrVhqeCYg9YP3JA86a7pHqMEp7N3lze4dDB1emnIZ9OBiomJXKY MvkzZRyohCG8bO4pm3ehEaHwHgb48M/yTv077yfLeIvMM/mQo/+iw4XTBY1mz+hjhk bLKZLcrFzcsiBELokBr0rA1Tyw5QE6M/6kQf8wCA= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-64531: net: openvswitch: reject oversized nested action attrs Date: Mon, 27 Jul 2026 08:32:30 +0200 Message-ID: <2026072732-CVE-2026-64531-e4ce@gregkh> X-Mailer: git-send-email 2.55.0 Reply-To: , Precedence: bulk X-Mailing-List: linux-cve-announce@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=4467; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=fvcX9/4Wq+kB7J5kF9iK5P5EcXRH0Nx/Lr4oYHp09Hw=; b=owGbwMvMwCRo6H6F97bub03G02pJDFlpvxsC93/5vGG3pDjHefkw7+S7+yZ0G73Vndnw7IhY0 Tqz5eVyHbEsDIJMDLJiiixftvEc3V9xSNHL0PY0zBxWJpAhDFycAjCRbGGGBatf5f/tXjQ/ZmvK rgfWbtMaf626F8EwP+3xo1/9h1KUPDv4ti52zH174UlDJgA= X-Developer-Key: i=gregkh@linuxfoundation.org; a=openpgp; fpr=F4B60CC5BF78C2214A313DCB3147D40DDB2DFB29 Content-Transfer-Encoding: 8bit From: Greg Kroah-Hartman Description =========== In the Linux kernel, the following vulnerability has been resolved: net: openvswitch: reject oversized nested action attrs Open vSwitch stores generated flow actions as nlattrs, whose nla_len field is u16. Commit a1e64addf3ff ("net: openvswitch: remove misbehaving actions length check") allowed the total sw_flow_actions stream to grow beyond 64 KiB, which is valid, but also removed the last guard preventing a generated nested action attribute from exceeding U16_MAX. An oversized generated container can thus be closed with a truncated nla_len. A later dump or teardown then walks a structurally different stream than the one that was validated. In particular, an oversized nested CLONE/CT action may cause subsequent bytes in the generated stream to be interpreted as independent actions. Keep the larger total-action-stream behavior, but make nested action close reject generated containers that do not fit in nla_len, and return the error through all callers. For recursive SAMPLE, CLONE, DEC_TTL, and CHECK_PKT_LEN builders, trim resource-owning action-list tails in reverse construction order before discarding failed wrappers, so resources copied into the rejected tails are released before the wrappers are removed. Most failed outer wrappers are discarded by truncating actions_len after child resources have been released. CHECK_PKT_LEN also trims its parent after branch resources are gone. SET/TUNNEL close failures unwind their known tun_dst ownership directly, and SET_TO_MASKED has no external ownership and truncates on close failure. The Linux kernel CVE team has assigned CVE-2026-64531 to this issue. Affected and fixed versions =========================== Issue introduced in 5.15.180 with commit 057dbc5b72e9fcac439cd561c3a539b8a0edeb92 and fixed in 5.15.212 with commit ab855641241387db062a5e41d9ad6b8561542572 Issue introduced in 6.1.132 with commit 2532adbfe917c0e71dba2650ffc6efe396314c87 and fixed in 6.1.178 with commit c66bd2626c2764f23764ff0f8277f44a9cfe8349 Issue introduced in 6.6.84 with commit 4b1a0ee6164c7204c68ab5a9c48c07bfe8852485 and fixed in 6.6.145 with commit d573250d228401f707f4dbc09d11227a6215ee5f Issue introduced in 6.12.20 with commit e6610f9c08b4c04cf7949c10fc246c071d00e935 and fixed in 6.12.97 with commit f1efff8858403191361a01269c6fe8dd7f55a385 Issue introduced in 6.14 with commit a1e64addf3ff9257b45b78bc7d743781c3f41340 and fixed in 6.18.40 with commit dbd14f736be02cfe73049bd801af89becd1a0749 Issue introduced in 6.14 with commit a1e64addf3ff9257b45b78bc7d743781c3f41340 and fixed in 7.1.5 with commit 1b41cbe05b184f8861712f0806cc0c4f5d8c6dfe Issue introduced in 6.14 with commit a1e64addf3ff9257b45b78bc7d743781c3f41340 and fixed in 7.2-rc4 with commit 3f1f755366687d051174739fb99f7d560202f60b Issue introduced in 6.13.8 with commit 6b099d285d7ed324494b6d684f377aa103856118 Please see https://www.kernel.org for a full list of currently supported kernel versions by the kernel community. Unaffected versions might change over time as fixes are backported to older supported kernel versions. The official CVE entry at https://cve.org/CVERecord/?id=CVE-2026-64531 will be updated if fixes are backported, please check that for the most up to date information about this issue. Affected files ============== The file(s) affected by this issue are: net/openvswitch/flow_netlink.c Mitigation ========== The Linux kernel CVE team recommends that you update to the latest stable kernel version for this, and many other bugfixes. Individual changes are never tested alone, but rather are part of a larger kernel release. Cherry-picking individual commits is not recommended or supported by the Linux kernel community at all. If however, updating to the latest release is impossible, the individual changes to resolve this issue can be found at these commits: https://git.kernel.org/stable/c/ab855641241387db062a5e41d9ad6b8561542572 https://git.kernel.org/stable/c/c66bd2626c2764f23764ff0f8277f44a9cfe8349 https://git.kernel.org/stable/c/d573250d228401f707f4dbc09d11227a6215ee5f https://git.kernel.org/stable/c/f1efff8858403191361a01269c6fe8dd7f55a385 https://git.kernel.org/stable/c/dbd14f736be02cfe73049bd801af89becd1a0749 https://git.kernel.org/stable/c/1b41cbe05b184f8861712f0806cc0c4f5d8c6dfe https://git.kernel.org/stable/c/3f1f755366687d051174739fb99f7d560202f60b