{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-23004",
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "state": "PUBLISHED",
        "assignerShortName": "Linux",
        "dateReserved": "2026-01-13T15:37:45.939Z",
        "datePublished": "2026-01-25T14:36:18.233Z",
        "dateUpdated": "2026-08-05T12:20:06.610Z"
    },
    "containers": {
        "cna": {
            "providerMetadata": {
                "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
                "shortName": "Linux",
                "dateUpdated": "2026-08-05T12:20:06.610Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndst: fix races in rt6_uncached_list_del() and rt_del_uncached_list()\n\nsyzbot was able to crash the kernel in rt6_uncached_list_flush_dev()\nin an interesting way [1]\n\nCrash happens in list_del_init()/INIT_LIST_HEAD() while writing\nlist->prev, while the prior write on list->next went well.\n\nstatic inline void INIT_LIST_HEAD(struct list_head *list)\n{\n\tWRITE_ONCE(list->next, list); // This went well\n\tWRITE_ONCE(list->prev, list); // Crash, @list has been freed.\n}\n\nIssue here is that rt6_uncached_list_del() did not attempt to lock\nul->lock, as list_empty(&rt->dst.rt_uncached) returned\ntrue because the WRITE_ONCE(list->next, list) happened on the other CPU.\n\nWe might use list_del_init_careful() and list_empty_careful(),\nor make sure rt6_uncached_list_del() always grabs the spinlock\nwhenever rt->dst.rt_uncached_list has been set.\n\nA similar fix is neeed for IPv4.\n\n[1]\n\n BUG: KASAN: slab-use-after-free in INIT_LIST_HEAD include/linux/list.h:46 [inline]\n BUG: KASAN: slab-use-after-free in list_del_init include/linux/list.h:296 [inline]\n BUG: KASAN: slab-use-after-free in rt6_uncached_list_flush_dev net/ipv6/route.c:191 [inline]\n BUG: KASAN: slab-use-after-free in rt6_disable_ip+0x633/0x730 net/ipv6/route.c:5020\nWrite of size 8 at addr ffff8880294cfa78 by task kworker/u8:14/3450\n\nCPU: 0 UID: 0 PID: 3450 Comm: kworker/u8:14 Tainted: G             L      syzkaller #0 PREEMPT_{RT,(full)}\nTainted: [L]=SOFTLOCKUP\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025\nWorkqueue: netns cleanup_net\nCall Trace:\n <TASK>\n  dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120\n  print_address_description mm/kasan/report.c:378 [inline]\n  print_report+0xca/0x240 mm/kasan/report.c:482\n  kasan_report+0x118/0x150 mm/kasan/report.c:595\n  INIT_LIST_HEAD include/linux/list.h:46 [inline]\n  list_del_init include/linux/list.h:296 [inline]\n  rt6_uncached_list_flush_dev net/ipv6/route.c:191 [inline]\n  rt6_disable_ip+0x633/0x730 net/ipv6/route.c:5020\n  addrconf_ifdown+0x143/0x18a0 net/ipv6/addrconf.c:3853\n addrconf_notify+0x1bc/0x1050 net/ipv6/addrconf.c:-1\n  notifier_call_chain+0x19d/0x3a0 kernel/notifier.c:85\n  call_netdevice_notifiers_extack net/core/dev.c:2268 [inline]\n  call_netdevice_notifiers net/core/dev.c:2282 [inline]\n  netif_close_many+0x29c/0x410 net/core/dev.c:1785\n  unregister_netdevice_many_notify+0xb50/0x2330 net/core/dev.c:12353\n  ops_exit_rtnl_list net/core/net_namespace.c:187 [inline]\n  ops_undo_list+0x3dc/0x990 net/core/net_namespace.c:248\n  cleanup_net+0x4de/0x7b0 net/core/net_namespace.c:696\n  process_one_work kernel/workqueue.c:3257 [inline]\n  process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340\n  worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421\n  kthread+0x711/0x8a0 kernel/kthread.c:463\n  ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158\n  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246\n </TASK>\n\nAllocated by task 803:\n  kasan_save_stack mm/kasan/common.c:57 [inline]\n  kasan_save_track+0x3e/0x80 mm/kasan/common.c:78\n  unpoison_slab_object mm/kasan/common.c:340 [inline]\n  __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366\n  kasan_slab_alloc include/linux/kasan.h:253 [inline]\n  slab_post_alloc_hook mm/slub.c:4953 [inline]\n  slab_alloc_node mm/slub.c:5263 [inline]\n  kmem_cache_alloc_noprof+0x18d/0x6c0 mm/slub.c:5270\n  dst_alloc+0x105/0x170 net/core/dst.c:89\n  ip6_dst_alloc net/ipv6/route.c:342 [inline]\n  icmp6_dst_alloc+0x75/0x460 net/ipv6/route.c:3333\n  mld_sendpack+0x683/0xe60 net/ipv6/mcast.c:1844\n  mld_send_cr net/ipv6/mcast.c:2154 [inline]\n  mld_ifc_work+0x83e/0xd60 net/ipv6/mcast.c:2693\n  process_one_work kernel/workqueue.c:3257 [inline]\n  process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340\n  worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421\n  kthread+0x711/0x8a0 kernel/kthread.c:463\n  ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158\n  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entr\n---truncated---"
                }
            ],
            "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 vulnerable IPv4/IPv6 dst uncached-list paths are reachable through local network namespace operations and local packet/socket activity rather than unauthenticated remote packets alone. A local attacker can use user namespaces to obtain CAP_NET_ADMIN in a new network namespace and drive route creation plus device/netns teardown.\nAC:L - The bug is a race, but the attacker can plausibly control both sides by repeatedly creating/freeing uncached dst objects and concurrently tearing down devices or network namespaces. No rare external condition is required beyond normal kernel scheduling.\nPR:L - The relevant device and route teardown paths require CAP_NET_ADMIN, but rtnetlink checks it against the target network namespace user_ns. An unprivileged local user can obtain those capabilities in a user-created network namespace on systems allowing user namespaces.\nUI:N - Exploitation does not require a victim user to open a file, mount anything, or perform an action. The attacker can trigger the route allocation/free and teardown sequence directly.\nS:U - The corruption occurs inside the host kernel networking stack and impacts resources governed by the same kernel security authority. It is not a guest-to-host escape or other cross-scope boundary bypass.\nC:H - This is a slab use-after-free involving dst/route objects, and kernel UAF memory corruption can be leveraged with heap shaping for disclosure primitives. When uncertain, the higher severity confidentiality impact is appropriate.\nI:H - The race causes a write through list_del_init into freed route memory, creating kernel heap corruption. Such UAF writes are plausibly exploitable for arbitrary write or control-flow corruption, so integrity impact is high.\nA:H - The upstream report demonstrates a KASAN slab-use-after-free crash in rt6_uncached_list_flush_dev during netns cleanup. Repeated triggering can crash or destabilize the kernel."
                        }
                    ]
                }
            ],
            "affected": [
                {
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "unaffected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "net/core/dst.c",
                        "net/ipv4/route.c",
                        "net/ipv6/route.c"
                    ],
                    "versions": [
                        {
                            "version": "78df76a065ae3b5dbcb9a29912adc02f697de498",
                            "lessThan": "815db2363e51f0ef416947492d4dac5b7a520f56",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "78df76a065ae3b5dbcb9a29912adc02f697de498",
                            "lessThan": "f24a52948c95e02facbca2b3b6eb5a225e27eb01",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "78df76a065ae3b5dbcb9a29912adc02f697de498",
                            "lessThan": "722de945216144af7cd4d39bdeb936108d2595a7",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "78df76a065ae3b5dbcb9a29912adc02f697de498",
                            "lessThan": "9a6f0c4d5796ab89b5a28a890ce542344d58bd69",
                            "status": "affected",
                            "versionType": "git"
                        }
                    ]
                },
                {
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "affected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "net/core/dst.c",
                        "net/ipv4/route.c",
                        "net/ipv6/route.c"
                    ],
                    "versions": [
                        {
                            "version": "3.6",
                            "status": "affected"
                        },
                        {
                            "version": "0",
                            "lessThan": "3.6",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.6.130",
                            "lessThanOrEqual": "6.6.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.12.78",
                            "lessThanOrEqual": "6.12.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.18.7",
                            "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": "3.6",
                                    "versionEndExcluding": "6.6.130"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "3.6",
                                    "versionEndExcluding": "6.12.78"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "3.6",
                                    "versionEndExcluding": "6.18.7"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "3.6",
                                    "versionEndExcluding": "6.19"
                                }
                            ]
                        }
                    ]
                }
            ],
            "references": [
                {
                    "url": "https://git.kernel.org/stable/c/815db2363e51f0ef416947492d4dac5b7a520f56"
                },
                {
                    "url": "https://git.kernel.org/stable/c/f24a52948c95e02facbca2b3b6eb5a225e27eb01"
                },
                {
                    "url": "https://git.kernel.org/stable/c/722de945216144af7cd4d39bdeb936108d2595a7"
                },
                {
                    "url": "https://git.kernel.org/stable/c/9a6f0c4d5796ab89b5a28a890ce542344d58bd69"
                }
            ],
            "title": "dst: fix races in rt6_uncached_list_del() and rt_del_uncached_list()",
            "x_generator": {
                "engine": "bippy-1.2.0"
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    }
}