{ "schema_version": "1.6.1", "id": "RPI-CVE-2023-52574", "modified": "2026-10-09T11:39:44Z", "upstream": [ "CVE-2023-52574" ], "published": "2024-03-02T22:00:33Z", "summary": "team: fix null-ptr-deref when team device type is changed", "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nteam: fix null-ptr-deref when team device type is changed\n\nGet a null-ptr-deref bug as follows with reproducer [1].\n\nBUG: kernel NULL pointer dereference, address: 0000000000000228\n...\nRIP: 0010:vlan_dev_hard_header+0x35/0x140 [8021q]\n...\nCall Trace:\n \n ? __die+0x24/0x70\n ? page_fault_oops+0x82/0x150\n ? exc_page_fault+0x69/0x150\n ? asm_exc_page_fault+0x26/0x30\n ? vlan_dev_hard_header+0x35/0x140 [8021q]\n ? vlan_dev_hard_header+0x8e/0x140 [8021q]\n neigh_connected_output+0xb2/0x100\n ip6_finish_output2+0x1cb/0x520\n ? nf_hook_slow+0x43/0xc0\n ? ip6_mtu+0x46/0x80\n ip6_finish_output+0x2a/0xb0\n mld_sendpack+0x18f/0x250\n mld_ifc_work+0x39/0x160\n process_one_work+0x1e6/0x3f0\n worker_thread+0x4d/0x2f0\n ? __pfx_worker_thread+0x10/0x10\n kthread+0xe5/0x120\n ? __pfx_kthread+0x10/0x10\n ret_from_fork+0x34/0x50\n ? __pfx_kthread+0x10/0x10\n ret_from_fork_asm+0x1b/0x30\n\n[1]\n$ teamd -t team0 -d -c '{\"runner\": {\"name\": \"loadbalance\"}}'\n$ ip link add name t-dummy type dummy\n$ ip link add link t-dummy name t-dummy.100 type vlan id 100\n$ ip link add name t-nlmon type nlmon\n$ ip link set t-nlmon master team0\n$ ip link set t-nlmon nomaster\n$ ip link set t-dummy up\n$ ip link set team0 up\n$ ip link set t-dummy.100 down\n$ ip link set t-dummy.100 master team0\n\nWhen enslave a vlan device to team device and team device type is changed\nfrom non-ether to ether, header_ops of team device is changed to\nvlan_header_ops. That is incorrect and will trigger null-ptr-deref\nfor vlan->real_dev in vlan_dev_hard_header() because team device is not\na vlan device.\n\nCache eth_header_ops in team_setup(), then assign cached header_ops to\nheader_ops of team net device when its type is changed from non-ether\nto ether to fix the bug.", "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": [ "1:6.1.47-1+rpt4" ], "ecosystem_specific": { "binaries": [ { "binary_name": "linux-image-6.1.0-rpi3-rpi-2712", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v6", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v7", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v7l", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v8", "binary_version": "1:6.1.47-1+rpt4" } ] }, "database_specific": { "per_version": { "1:6.1.47-1+rpt4": { "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e", "upstream_version": "6.1.47", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.1.56", "compiled_filter": false } } } } ], "references": [ { "type": "ADVISORY", "url": "https://www.cve.org/CVERecord?id=CVE-2023-52574" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/1779eb51b9cc628cee551f252701a85a2a50a457" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/a7fb47b9711101d2405b0eb1276fb1f9b9b270c7" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/c5f6478686bb45f453031594ae19b6c9723a780d" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/b44dd92e2afd89eb6e9d27616858e72a67bdc1a7" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/cd05eec2ee0cc396813a32ef675634e403748255" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/2f0acb0736ecc3eb85dc80ad2790d634dcb10b58" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/cac50d9f5d876be32cb9aa21c74018468900284d" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/492032760127251e5540a5716a70996bacf2a3fd" } ], "database_specific": { "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git", "upstream_modified": "2026-08-05T11:24:39Z", "severity": { "source": "kernel CNA", "cvss_v3_score": 7.8, "cvss_v3_severity": "High", "scenario": "AV:L - The bug is triggered by local rtnetlink configuration (creating a team device and enslaving nlmon then vlan ports via IFLA_MASTER), not by processing unauthenticated remote packets; subsequent hard_header calls occur on that locally configured device.\nAC:L - The reproducer topology is fully attacker-controlled and deterministically installs vlan_header_ops on the team device when changing type from non-ether to ether; no race or external timing condition is required.\nPR:L - Creating team/dummy/vlan/nlmon devices and enslaving them requires CAP_NET_ADMIN enforced via netlink_net_capable() in the network namespace's user_ns, which an unprivileged user obtains with unshare -Urn; GENL_ADMIN_PERM (init userns) is not required for this path.\nUI:N - The attacker configures the devices and triggers packet transmission (e.g., IPv6 MLD on bring-up or local socket send) without any action by another user.\nS:U - Impact remains within the same kernel security authority (local DoS / type-confusion privilege impact); there is no VM escape, IOMMU bypass, or other cross-boundary effect.\nC:H - Installing vlan_header_ops on a non-vlan team device is header_ops type confusion: vlan_dev_hard_header interprets team private data as vlan_dev_priv (including pointer walks such as egress_priority_map), which can expose kernel memory; scored high per type-confusion guidance and CVE-2026-31502.\nI:H - Type confusion in kernel header_ops callback dispatch misinterprets object layout and can yield write/control-flow primitives beyond the observed crash; kernel type confusion is scored as high integrity impact.\nA:H - The demonstrated failure mode is a kernel NULL pointer dereference oops in vlan_dev_hard_header when the confused real_dev/layout is used, which is a high availability impact." } } }