{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-68801", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-12-24T10:30:51.045Z", "datePublished": "2026-01-13T15:29:10.349Z", "dateUpdated": "2026-08-05T12:11:35.171Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:11:35.171Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmlxsw: spectrum_router: Fix neighbour use-after-free\n\nWe sometimes observe use-after-free when dereferencing a neighbour [1].\nThe problem seems to be that the driver stores a pointer to the\nneighbour, but without holding a reference on it. A reference is only\ntaken when the neighbour is used by a nexthop.\n\nFix by simplifying the reference counting scheme. Always take a\nreference when storing a neighbour pointer in a neighbour entry. Avoid\ntaking a referencing when the neighbour is used by a nexthop as the\nneighbour entry associated with the nexthop already holds a reference.\n\nTested by running the test that uncovered the problem over 300 times.\nWithout this patch the problem was reproduced after a handful of\niterations.\n\n[1]\nBUG: KASAN: slab-use-after-free in mlxsw_sp_neigh_entry_update+0x2d4/0x310\nRead of size 8 at addr ffff88817f8e3420 by task ip/3929\n\nCPU: 3 UID: 0 PID: 3929 Comm: ip Not tainted 6.18.0-rc4-virtme-g36b21a067510 #3 PREEMPT(full)\nHardware name: Nvidia SN5600/VMOD0013, BIOS 5.13 05/31/2023\nCall Trace:\n \n dump_stack_lvl+0x6f/0xa0\n print_address_description.constprop.0+0x6e/0x300\n print_report+0xfc/0x1fb\n kasan_report+0xe4/0x110\n mlxsw_sp_neigh_entry_update+0x2d4/0x310\n mlxsw_sp_router_rif_gone_sync+0x35f/0x510\n mlxsw_sp_rif_destroy+0x1ea/0x730\n mlxsw_sp_inetaddr_port_vlan_event+0xa1/0x1b0\n __mlxsw_sp_inetaddr_lag_event+0xcc/0x130\n __mlxsw_sp_inetaddr_event+0xf5/0x3c0\n mlxsw_sp_router_netdevice_event+0x1015/0x1580\n notifier_call_chain+0xcc/0x150\n call_netdevice_notifiers_info+0x7e/0x100\n __netdev_upper_dev_unlink+0x10b/0x210\n netdev_upper_dev_unlink+0x79/0xa0\n vrf_del_slave+0x18/0x50\n do_set_master+0x146/0x7d0\n do_setlink.isra.0+0x9a0/0x2880\n rtnl_newlink+0x637/0xb20\n rtnetlink_rcv_msg+0x6fe/0xb90\n netlink_rcv_skb+0x123/0x380\n netlink_unicast+0x4a3/0x770\n netlink_sendmsg+0x75b/0xc90\n __sock_sendmsg+0xbe/0x160\n ____sys_sendmsg+0x5b2/0x7d0\n ___sys_sendmsg+0xfd/0x180\n __sys_sendmsg+0x124/0x1c0\n do_syscall_64+0xbb/0xfd0\n entry_SYSCALL_64_after_hwframe+0x4b/0x53\n[...]\n\nAllocated by task 109:\n kasan_save_stack+0x30/0x50\n kasan_save_track+0x14/0x30\n __kasan_kmalloc+0x7b/0x90\n __kmalloc_noprof+0x2c1/0x790\n neigh_alloc+0x6af/0x8f0\n ___neigh_create+0x63/0xe90\n mlxsw_sp_nexthop_neigh_init+0x430/0x7e0\n mlxsw_sp_nexthop_type_init+0x212/0x960\n mlxsw_sp_nexthop6_group_info_init.constprop.0+0x81f/0x1280\n mlxsw_sp_nexthop6_group_get+0x392/0x6a0\n mlxsw_sp_fib6_entry_create+0x46a/0xfd0\n mlxsw_sp_router_fib6_replace+0x1ed/0x5f0\n mlxsw_sp_router_fib6_event_work+0x10a/0x2a0\n process_one_work+0xd57/0x1390\n worker_thread+0x4d6/0xd40\n kthread+0x355/0x5b0\n ret_from_fork+0x1d4/0x270\n ret_from_fork_asm+0x11/0x20\n\nFreed by task 154:\n kasan_save_stack+0x30/0x50\n kasan_save_track+0x14/0x30\n __kasan_save_free_info+0x3b/0x60\n __kasan_slab_free+0x43/0x70\n kmem_cache_free_bulk.part.0+0x1eb/0x5e0\n kvfree_rcu_bulk+0x1f2/0x260\n kfree_rcu_work+0x130/0x1b0\n process_one_work+0xd57/0x1390\n worker_thread+0x4d6/0xd40\n kthread+0x355/0x5b0\n ret_from_fork+0x1d4/0x270\n ret_from_fork_asm+0x11/0x20\n\nLast potentially related work creation:\n kasan_save_stack+0x30/0x50\n kasan_record_aux_stack+0x8c/0xa0\n kvfree_call_rcu+0x93/0x5b0\n mlxsw_sp_router_neigh_event_work+0x67d/0x860\n process_one_work+0xd57/0x1390\n worker_thread+0x4d6/0xd40\n kthread+0x355/0x5b0\n ret_from_fork+0x1d4/0x270\n ret_from_fork_asm+0x11/0x20" } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The stale neighbour pointer is dereferenced through local netlink operations, including unprivileged devlink DPIPE queries; received packets alone cannot complete exploitation.\nAC:L - An attacker can churn neighbour entries and repeatedly trigger the dereference, and the flaw reproduced after only a few iterations. No race condition beyond the attacker's practical influence is required.\nPR:L - The demonstrated VRF-detach path requires init-namespace CAP_NET_ADMIN, but DEVLINK_CMD_DPIPE_ENTRIES_GET lacks GENL_ADMIN_PERM and dereferences the same stale pointer. A basic local user can therefore reach the vulnerable object.\nUI:N - Once the vulnerable neighbour state exists, the attacker can issue the triggering netlink requests without another user's participation.\nS:U - The corruption occurs within the host kernel and does not inherently cross a VM, IOMMU, or other distinct security authority.\nC:H - The freed neighbour's table pointer and primary key are read, with address bytes potentially returned through DPIPE. Heap reclamation and spraying make broader kernel-memory disclosure defensible.\nI:H - mlxsw_sp_neigh_entry_update() performs a read-modify-write on the freed object's flags field. Reclaiming the allocation can therefore corrupt another heap object and potentially enable control-flow hijacking.\nA:H - Dereferencing the reclaimed table pointer or corrupting the replacement object can cause an oops or kernel panic. The trigger can be repeated until the failure occurs." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c" ], "versions": [ { "version": "6cf3c971dc84cb36579515ddb488919b9e9fb6de", "lessThan": "a2dfe6758fc63e542105bee8b17a3a7485684db0", "status": "affected", "versionType": "git" }, { "version": "6cf3c971dc84cb36579515ddb488919b9e9fb6de", "lessThan": "9e0a0d9eeb0dbeba2c83fa837885b19b8b9230fc", "status": "affected", "versionType": "git" }, { "version": "6cf3c971dc84cb36579515ddb488919b9e9fb6de", "lessThan": "c437fbfd4382412598cdda1f8e2881b523668cc2", "status": "affected", "versionType": "git" }, { "version": "6cf3c971dc84cb36579515ddb488919b9e9fb6de", "lessThan": "4a3c569005f42ab5e5b2ad637132a33bf102cc08", "status": "affected", "versionType": "git" }, { "version": "6cf3c971dc84cb36579515ddb488919b9e9fb6de", "lessThan": "ed8141b206bdcfd5d0b92c90832eeb77b7a60a0a", "status": "affected", "versionType": "git" }, { "version": "6cf3c971dc84cb36579515ddb488919b9e9fb6de", "lessThan": "675c5aeadf6472672c472dc0f26401e4fcfbf254", "status": "affected", "versionType": "git" }, { "version": "6cf3c971dc84cb36579515ddb488919b9e9fb6de", "lessThan": "8b0e69763ef948fb872a7767df4be665d18f5fd4", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c" ], "versions": [ { "version": "4.8", "status": "affected" }, { "version": "0", "lessThan": "4.8", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.248", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.198", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.160", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.120", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.64", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.3", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.19", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.8", "versionEndExcluding": "5.10.248" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.8", "versionEndExcluding": "5.15.198" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.8", "versionEndExcluding": "6.1.160" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.8", "versionEndExcluding": "6.6.120" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.8", "versionEndExcluding": "6.12.64" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.8", "versionEndExcluding": "6.18.3" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.8", "versionEndExcluding": "6.19" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/a2dfe6758fc63e542105bee8b17a3a7485684db0" }, { "url": "https://git.kernel.org/stable/c/9e0a0d9eeb0dbeba2c83fa837885b19b8b9230fc" }, { "url": "https://git.kernel.org/stable/c/c437fbfd4382412598cdda1f8e2881b523668cc2" }, { "url": "https://git.kernel.org/stable/c/4a3c569005f42ab5e5b2ad637132a33bf102cc08" }, { "url": "https://git.kernel.org/stable/c/ed8141b206bdcfd5d0b92c90832eeb77b7a60a0a" }, { "url": "https://git.kernel.org/stable/c/675c5aeadf6472672c472dc0f26401e4fcfbf254" }, { "url": "https://git.kernel.org/stable/c/8b0e69763ef948fb872a7767df4be665d18f5fd4" } ], "title": "mlxsw: spectrum_router: Fix neighbour use-after-free", "x_generator": { "engine": "bippy-1.2.0" } } } }