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 EBBEC4CDDD3 for ; Thu, 17 Sep 2026 16:21:16 +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=1789662079; cv=none; b=rHxviJEfcgkOY1McrKEuZqEuffhH2QE/QxI4A/rKQaBBTMXUeL9r5I1hrMgQhuJ9qU4Bz5eBdCXQDqQXQoqdT6ht4X1ZDgKFlMLfexH99kLXbDmU2nUzQteMR7ceeyyn6yfbuT5pv0y2t6nUkuTmCYQ0pAspo684qJKEA+hbp6k= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789662079; c=relaxed/simple; bh=PRM2GwzByK4H0WcJYfTKeVGPGScvqZSxuYdplQ8RwV8=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=JrXCUDOhpiQ9jVIKs6Qb5qM5zsUDRdUljK+o6D5fdYp0bBy8kBgfoylHFpxSxkffzte6eavW7SqiuT6MJEK9tdiKnIEitkTqAd8nwh8uk2bUpgiLIfr5ltj21k8Tl6/kTZZR8J8P/iRNprPAAtXwIvMvnG7wO16y7QpjZOSmIqY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=0Eho0t6q; 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="0Eho0t6q" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4BFDF1F000FF; Thu, 17 Sep 2026 16:21:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789662076; bh=4iKTvswGNY8CmS2YKxvC3FPjxOXPrpULCskA/kDmcXg=; h=From:To:Cc:Subject:Date:Reply-To; b=0Eho0t6q2Pe8f7XT3qDywysFIs0pr2nY4as3fo6PRUNCcuXDBornYIAH31CKeY7fq YA0ufwGaybA1R1Z7xK7MvQrqlRfnHMQwxg4qmmBydYibx/SJPlymCuNALOUErT3P7i yH1zSQ/y4Qz/VknIyqxJJ07/iHWWT4LG6wEHfV6M= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-90232: amt: Don't support cross-netns setup. Date: Thu, 17 Sep 2026 17:11:02 +0100 Message-ID: <2026091740-CVE-2026-90232-b0c2@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=5009; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=rdJIOvxB6Qj6C34xmy/btvHv2YPzyN/h8VavnIYh4xQ=; b=owGbwMvMwCRo6H6F97bub03G02pJDFlrBDry017v9rwir7xTcZsWny+/a2dIvu5Trs+fL/0ra 38z2eR2RywLgyATg6yYIsuXbTxH91ccUvQytD0NM4eVCWQIAxenAEyEp4lhfuUW/0090hFSk3f8 XxrS/sjmrFXwAoYFNyceFV1+TfF84tqm1T1ZnwwPTZtZDwA= 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: amt: Don't support cross-netns setup. When a lower device is unregistered, amt_device_event() tries to unregister its upper AMT device, but it has two problems. 1. amt_lookup_upper_dev() looks up an upper device in the lower device's netns only 2. amt_device_event() unregisters a single upper device only If AMT device is created on a lower device in another netns, removing the lower device triggers the splat below and gets stuck until all upper devices are removed. [0] The cross-netns setup seems unintentional considering 1. and the following points: * amt_link_setup() sets dev->netns_immutable to true * skb_scrub_packet() is not called in the fast path * iproute2 binary fails to find cross-netns lower device via link-netns: # ip -n ns1 link add amt0 link-netns ns2 type amt dev veth1 Cannot find device "veth1" Instead of supporting it properly and preparing for per-netns netdev unreg, let's forbid cross-netns setup. Note that the problem 2. needs a separate fix. [0]: WARNING: net/core/dev.c:12518 at unregister_netdevice_many_notify+0x1cce/0x2250, CPU#48: ip/2031 Modules linked in: CPU: 48 UID: 0 PID: 2031 Comm: ip Not tainted 7.2.0-rc5+ #27 PREEMPT(full) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-debian-1.17.0-1 04/01/2014 RIP: 0010:unregister_netdevice_many_notify (net/core/dev.c:12518) Code: 89 ef e8 d5 52 ae fe e9 d0 f4 ff ff 48 8d 3d f9 3b 9c 02 48 c7 c6 c0 0b 63 84 ba ab 1f 00 00 67 48 0f b9 3a e9 65 ff ff ff 90 <0f> 0b 90 eb 81 48 8d 3d f6 3b 9c 02 48 c7 c6 c0 0b 63 84 ba e2 1f RSP: 0018:ffffc90004abf160 EFLAGS: 00010212 RAX: ffff888104d38260 RBX: ffff88800b0911b8 RCX: dffffc0000000000 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff85b9f880 RBP: ffffc90004abf2d0 R08: ffffffff85b9f887 R09: 1ffffffff0b73f10 R10: dffffc0000000000 R11: fffffbfff0b73f11 R12: ffff88800b091d08 R13: ffff88800b091178 R14: dffffc0000000000 R15: ffff88800b091000 FS: 00007f555b86c600(0000) GS:ffff8881942a0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000562107d489c0 CR3: 0000000109a40002 CR4: 0000000000372ef0 Call Trace: rtnl_dellink (net/core/rtnetlink.c:3632 net/core/rtnetlink.c:3674) rtnetlink_rcv_msg (net/core/rtnetlink.c:7112) netlink_rcv_skb (net/netlink/af_netlink.c:2556) netlink_unicast (net/netlink/af_netlink.c:1319) netlink_sendmsg (net/netlink/af_netlink.c:1900) ____sys_sendmsg (net/socket.c:775) __sys_sendmsg (net/socket.c:2738) do_syscall_64 (arch/x86/entry/syscall_64.c:63) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121) ... unregister_netdevice: waiting for veth0 to become free. Usage count = 7 ref_tracker: netdev@ffff88800d7496d8 has 3/3 users at __netdev_adjacent_dev_insert (./include/linux/netdevice.h:4525 ./include/linux/netdevice.h:4554 net/core/dev.c:8791) __netdev_upper_dev_link (net/core/dev.c:8879 net/core/dev.c:8963) netdev_upper_dev_link (net/core/dev.c:9009) amt_newlink (drivers/net/amt.c:3321) The Linux kernel CVE team has assigned CVE-2026-90232 to this issue. Affected and fixed versions =========================== Issue introduced in 5.16 with commit b9022b53adad88fd6cf2b9718c9e498504f3e1dd and fixed in 6.18.52 with commit 569eb11f0990849ba48706a2bfa743273707e254 Issue introduced in 5.16 with commit b9022b53adad88fd6cf2b9718c9e498504f3e1dd and fixed in 7.2.6 with commit e1dc0af719a2566ae7ccb82c0a11f70aa54908e9 Issue introduced in 5.16 with commit b9022b53adad88fd6cf2b9718c9e498504f3e1dd and fixed in 7.3-rc1 with commit e99ecc3046ea5f5c6b5e1f8b4ef854c6c6998e06 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-2026-90232 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: drivers/net/amt.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/569eb11f0990849ba48706a2bfa743273707e254 https://git.kernel.org/stable/c/e1dc0af719a2566ae7ccb82c0a11f70aa54908e9 https://git.kernel.org/stable/c/e99ecc3046ea5f5c6b5e1f8b4ef854c6c6998e06