{ "schema_version": "1.6.1", "id": "RPI-CVE-2026-31508", "modified": "2026-10-09T11:39:44Z", "upstream": [ "CVE-2026-31508" ], "published": "2026-04-22T13:57:42Z", "summary": "net: openvswitch: Avoid releasing netdev before teardown completes", "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: openvswitch: Avoid releasing netdev before teardown completes\n\nThe patch cited in the Fixes tag below changed the teardown code for\nOVS ports to no longer unconditionally take the RTNL. After this change,\nthe netdev_destroy() callback can proceed immediately to the call_rcu()\ninvocation if the IFF_OVS_DATAPATH flag is already cleared on the\nnetdev.\n\nThe ovs_netdev_detach_dev() function clears the flag before completing\nthe unregistration, and if it gets preempted after clearing the flag (as\ncan happen on an -rt kernel), netdev_destroy() can complete and the\ndevice can be freed before the unregistration completes. This leads to a\nsplat like:\n\n[ 998.393867] Oops: general protection fault, probably for non-canonical address 0xff00000001000239: 0000 [#1] SMP PTI\n[ 998.393877] CPU: 42 UID: 0 PID: 55177 Comm: ip Kdump: loaded Not tainted 6.12.0-211.1.1.el10_2.x86_64+rt #1 PREEMPT_RT\n[ 998.393886] Hardware name: Dell Inc. PowerEdge R740/0JMK61, BIOS 2.24.0 03/27/2025\n[ 998.393889] RIP: 0010:dev_set_promiscuity+0x8d/0xa0\n[ 998.393901] Code: 00 00 75 d8 48 8b 53 08 48 83 ba b0 02 00 00 00 75 ca 48 83 c4 08 5b c3 cc cc cc cc 48 83 bf 48 09 00 00 00 75 91 48 8b 47 08 <48> 83 b8 b0 02 00 00 00 74 97 eb 81 0f 1f 80 00 00 00 00 90 90 90\n[ 998.393906] RSP: 0018:ffffce5864a5f6a0 EFLAGS: 00010246\n[ 998.393912] RAX: ff00000000ffff89 RBX: ffff894d0adf5a05 RCX: 0000000000000000\n[ 998.393917] RDX: 0000000000000000 RSI: 00000000ffffffff RDI: ffff894d0adf5a05\n[ 998.393921] RBP: ffff894d19252000 R08: ffff894d19252000 R09: 0000000000000000\n[ 998.393924] R10: ffff894d19252000 R11: ffff894d192521b8 R12: 0000000000000006\n[ 998.393927] R13: ffffce5864a5f738 R14: 00000000ffffffe2 R15: 0000000000000000\n[ 998.393931] FS: 00007fad61971800(0000) GS:ffff894cc0140000(0000) knlGS:0000000000000000\n[ 998.393936] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n[ 998.393940] CR2: 000055df0a2a6e40 CR3: 000000011c7fe003 CR4: 00000000007726f0\n[ 998.393944] PKRU: 55555554\n[ 998.393946] Call Trace:\n[ 998.393949] \n[ 998.393952] ? show_trace_log_lvl+0x1b0/0x2f0\n[ 998.393961] ? show_trace_log_lvl+0x1b0/0x2f0\n[ 998.393975] ? dp_device_event+0x41/0x80 [openvswitch]\n[ 998.394009] ? __die_body.cold+0x8/0x12\n[ 998.394016] ? die_addr+0x3c/0x60\n[ 998.394027] ? exc_general_protection+0x16d/0x390\n[ 998.394042] ? asm_exc_general_protection+0x26/0x30\n[ 998.394058] ? dev_set_promiscuity+0x8d/0xa0\n[ 998.394066] ? ovs_netdev_detach_dev+0x3a/0x80 [openvswitch]\n[ 998.394092] dp_device_event+0x41/0x80 [openvswitch]\n[ 998.394102] notifier_call_chain+0x5a/0xd0\n[ 998.394106] unregister_netdevice_many_notify+0x51b/0xa60\n[ 998.394110] rtnl_dellink+0x169/0x3e0\n[ 998.394121] ? rt_mutex_slowlock.constprop.0+0x95/0xd0\n[ 998.394125] rtnetlink_rcv_msg+0x142/0x3f0\n[ 998.394128] ? avc_has_perm_noaudit+0x69/0xf0\n[ 998.394130] ? __pfx_rtnetlink_rcv_msg+0x10/0x10\n[ 998.394132] netlink_rcv_skb+0x50/0x100\n[ 998.394138] netlink_unicast+0x292/0x3f0\n[ 998.394141] netlink_sendmsg+0x21b/0x470\n[ 998.394145] ____sys_sendmsg+0x39d/0x3d0\n[ 998.394149] ___sys_sendmsg+0x9a/0xe0\n[ 998.394156] __sys_sendmsg+0x7a/0xd0\n[ 998.394160] do_syscall_64+0x7f/0x170\n[ 998.394162] entry_SYSCALL_64_after_hwframe+0x76/0x7e\n[ 998.394165] RIP: 0033:0x7fad61bf4724\n[ 998.394188] Code: 89 02 b8 ff ff ff ff eb bb 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 f3 0f 1e fa 80 3d c5 e9 0c 00 00 74 13 b8 2e 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 54 c3 0f 1f 00 48 83 ec 28 89 54 24 1c 48 89\n[ 998.394189] RSP: 002b:00007ffd7e2f7cb8 EFLAGS: 00000202 ORIG_RAX: 000000000000002e\n[ 998.394191] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007fad61bf4724\n[ 998.394193] RDX: 0000000000000000 RSI: 00007ffd7e2f7d20 RDI: 0000000000000003\n[ 998.394194] RBP: 00007ffd7e2f7d90 R08: 0000000000000010 R09: 000000000000003f\n[ 998.394195] R10: 000055df11558010 R11: 0000000000000202 R12: 00007ffd7e2\n---truncated---", "severity": [ { "type": "CVSS_V3", "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H" } ], "affected": [ { "package": { "ecosystem": "Raspberry Pi OS:12", "name": "linux" }, "versions": [ "1:6.12.75-1+rpt1~bookworm" ], "ecosystem_specific": { "binaries": [ { "binary_name": "linux-image-6.12.75+rpt-rpi-2712", "binary_version": "1:6.12.75-1+rpt1~bookworm" }, { "binary_name": "linux-image-6.12.75+rpt-rpi-v6", "binary_version": "1:6.12.75-1+rpt1~bookworm" }, { "binary_name": "linux-image-6.12.75+rpt-rpi-v7", "binary_version": "1:6.12.75-1+rpt1~bookworm" }, { "binary_name": "linux-image-6.12.75+rpt-rpi-v7l", "binary_version": "1:6.12.75-1+rpt1~bookworm" }, { "binary_name": "linux-image-6.12.75+rpt-rpi-v8", "binary_version": "1:6.12.75-1+rpt1~bookworm" }, { "binary_name": "linux-image-6.12.75+rpt-rpi-v8-rt", "binary_version": "1:6.12.75-1+rpt1~bookworm" } ] }, "database_specific": { "per_version": { "1:6.12.75-1+rpt1~bookworm": { "linux_commit": "89050b1059997d38d55462b323b099a6436dc10d", "upstream_version": "6.12.75", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.12.80" } } } }, { "package": { "ecosystem": "Raspberry Pi OS:13", "name": "linux" }, "versions": [ "1:6.12.75-1+rpt1" ], "ecosystem_specific": { "binaries": [ { "binary_name": "linux-image-6.12.75+rpt-rpi-2712", "binary_version": "1:6.12.75-1+rpt1" }, { "binary_name": "linux-image-6.12.75+rpt-rpi-v6", "binary_version": "1:6.12.75-1+rpt1" }, { "binary_name": "linux-image-6.12.75+rpt-rpi-v7", "binary_version": "1:6.12.75-1+rpt1" }, { "binary_name": "linux-image-6.12.75+rpt-rpi-v8", "binary_version": "1:6.12.75-1+rpt1" }, { "binary_name": "linux-image-6.12.75+rpt-rpi-v8-rt", "binary_version": "1:6.12.75-1+rpt1" } ] }, "database_specific": { "per_version": { "1:6.12.75-1+rpt1": { "linux_commit": "89050b1059997d38d55462b323b099a6436dc10d", "upstream_version": "6.12.75", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.12.80" } } } } ], "references": [ { "type": "ADVISORY", "url": "https://www.cve.org/CVERecord?id=CVE-2026-31508" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/df3c95be76103604e752131d9495a24814915ece" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/33609454be4f582e686a4bf13d4482a5ca0f6c4b" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/5fdeaf591a0942772c2d18ff3563697a49ad01c6" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/4c3e25a7b711a402fcbbbcfbbdf2868ece1ae7c8" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/43579baa17270aa51f93eb09b6e4af6e047b7f6e" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/95265232b49765a4d00f4d028c100bb7185600f4" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/755a6300afbd743cda4b102f24f343380ec0e0ff" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/7c770dadfda5cbbde6aa3c4363ed513f1d212bf8" } ], "database_specific": { "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git", "upstream_modified": "2026-08-05T13:16:28Z", "severity": { "source": "kernel CNA", "cvss_v3_score": 7.8, "cvss_v3_severity": "High", "scenario": "AV:L - The vulnerable path is reached through local netlink/rtnetlink operations that create/delete Open vSwitch vports and delete the underlying netdevice. It is not directly reachable by remote network packets.\nAC:L - The bug is a teardown race, but an attacker with the needed namespace network privileges can control both sides by concurrently deleting the OVS vport/datapath and the attached netdevice. The race is repeatable through local operations, so complexity is low.\nPR:L - The OVS generic netlink commands require CAP_NET_ADMIN via GENL_UNS_ADMIN_PERM, and rtnetlink deletion requires CAP_NET_ADMIN in the socket network namespace. These are reachable with low privileges in deployments allowing unprivileged user and network namespaces.\nUI:N - No victim interaction is required once the attacker can issue the local netlink operations. The attacker can create and tear down the OVS/netdevice state directly.\nS:U - The impact is within the local kernel security authority. This is not a VM escape, IOMMU bypass, or cross-authority boundary change.\nC:H - The flaw can free the vport/net_device before teardown completes, producing a use-after-free on kernel objects. Under the required overestimating rule, this memory corruption is treated as capable of enabling kernel memory disclosure.\nI:H - The same use-after-free can plausibly be exploited with heap reuse/spraying to corrupt kernel state or hijack control flow. Therefore integrity impact is high.\nA:H - The reported failure is a kernel general protection fault during OVS/netdevice teardown. A local attacker can repeatedly trigger the race to crash or destabilize the kernel." } } }