{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2024-26631",
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "state": "PUBLISHED",
        "assignerShortName": "Linux",
        "dateReserved": "2024-02-19T14:20:24.136Z",
        "datePublished": "2024-03-18T10:07:48.346Z",
        "dateUpdated": "2026-08-05T11:26:24.727Z"
    },
    "containers": {
        "cna": {
            "providerMetadata": {
                "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
                "shortName": "Linux",
                "dateUpdated": "2026-08-05T11:26:24.727Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: mcast: fix data-race in ipv6_mc_down / mld_ifc_work\n\nidev->mc_ifc_count can be written over without proper locking.\n\nOriginally found by syzbot [1], fix this issue by encapsulating calls\nto mld_ifc_stop_work() (and mld_gq_stop_work() for good measure) with\nmutex_lock() and mutex_unlock() accordingly as these functions\nshould only be called with mc_lock per their declarations.\n\n[1]\nBUG: KCSAN: data-race in ipv6_mc_down / mld_ifc_work\n\nwrite to 0xffff88813a80c832 of 1 bytes by task 3771 on cpu 0:\n mld_ifc_stop_work net/ipv6/mcast.c:1080 [inline]\n ipv6_mc_down+0x10a/0x280 net/ipv6/mcast.c:2725\n addrconf_ifdown+0xe32/0xf10 net/ipv6/addrconf.c:3949\n addrconf_notify+0x310/0x980\n notifier_call_chain kernel/notifier.c:93 [inline]\n raw_notifier_call_chain+0x6b/0x1c0 kernel/notifier.c:461\n __dev_notify_flags+0x205/0x3d0\n dev_change_flags+0xab/0xd0 net/core/dev.c:8685\n do_setlink+0x9f6/0x2430 net/core/rtnetlink.c:2916\n rtnl_group_changelink net/core/rtnetlink.c:3458 [inline]\n __rtnl_newlink net/core/rtnetlink.c:3717 [inline]\n rtnl_newlink+0xbb3/0x1670 net/core/rtnetlink.c:3754\n rtnetlink_rcv_msg+0x807/0x8c0 net/core/rtnetlink.c:6558\n netlink_rcv_skb+0x126/0x220 net/netlink/af_netlink.c:2545\n rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:6576\n netlink_unicast_kernel net/netlink/af_netlink.c:1342 [inline]\n netlink_unicast+0x589/0x650 net/netlink/af_netlink.c:1368\n netlink_sendmsg+0x66e/0x770 net/netlink/af_netlink.c:1910\n ...\n\nwrite to 0xffff88813a80c832 of 1 bytes by task 22 on cpu 1:\n mld_ifc_work+0x54c/0x7b0 net/ipv6/mcast.c:2653\n process_one_work kernel/workqueue.c:2627 [inline]\n process_scheduled_works+0x5b8/0xa30 kernel/workqueue.c:2700\n worker_thread+0x525/0x730 kernel/workqueue.c:2781\n ..."
                }
            ],
            "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 `ipv6_mc_down()` side of the race is reached through local rtnetlink (`RTM_SETLINK`/`RTM_DELLINK` → `addrconf_notify`) and the opposing side through `setsockopt(IPV6_ADD_MEMBERSHIP)`, both local syscall interfaces. Although `mld_query_work` can additionally be fed by MLD query packets from a link-local peer, an adjacent attacker cannot initiate the interface-down half, so the self-contained attack is local.\nAC:L - The attacker drives both sides of the race deterministically and repeatedly: multicast join/leave and injected MLD queries queue `mc_ifc_work`/`mc_gq_work` while a concurrent thread loops `ip link set dev X down`, and `ipv6_mc_down()` uses non-sync `cancel_delayed_work()` for the query worker, guaranteeing an overlapping window on every iteration.\nPR:L - The rtnetlink gate is `netlink_net_capable(skb, CAP_NET_ADMIN)` → `netlink_ns_capable(..., sock_net(skb->sk)->user_ns, ...)`, which an unprivileged user obtains in a fresh netns via `unshare -Urn`; the multicast-join side requires no privilege at all.\nUI:N - The attacker performs every step — creating the device, joining groups, injecting MLD queries, and toggling the link down — with no victim action required.\nS:U - The corruption is confined to kernel IPv6 multicast state and the `inet6_dev` object within the same kernel security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - The unserialized `cancel_delayed_work()`/`in6_dev_hold()` window permits an `idev->refcnt` underflow through `__in6_dev_put()`'s unchecked `refcount_dec()`, leading to premature `kfree(idev)` while MLD workers still dereference it; a use-after-free on a kmalloc'd `inet6_dev` gives the attacker reads of resprayed heap contents.\nI:H - The same use-after-free is a write primitive: `struct inet6_dev` embeds five `delayed_work` structures whose `work->func` pointers the workqueue dispatches, plus `rs_timer` and `nd_parms`, so a resprayed object yields control-flow hijack; the race also corrupts adjacent packed fields (`mc_qrv`, `mc_gq_running`) that steer subsequent MLD state.\nA:H - The opposite interleaving orphans an `inet6_dev` reference so `in6_dev_finish_destroy()`/`netdev_put()` never run, wedging `unregister_netdevice: waiting for … to become free` permanently and blocking netns teardown under rtnl; the underflow direction produces `refcount_t` warnings and an oops."
                        }
                    ]
                }
            ],
            "affected": [
                {
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "unaffected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "net/ipv6/mcast.c"
                    ],
                    "versions": [
                        {
                            "version": "07a7a183f22cf1e3ce5ed336fe62a6248a2f6738",
                            "lessThan": "75ddcd741d2a30696f5893bc71a9d28f4ef22311",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "2d9a93b4902be6a5504b5941dd15e9cd776aadca",
                            "lessThan": "62b3387beef11738eb6ce667601a28fa089fa02c",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "2d9a93b4902be6a5504b5941dd15e9cd776aadca",
                            "lessThan": "380540bb06bb1d1b12bdc947d1b8f56cda6b5663",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "2d9a93b4902be6a5504b5941dd15e9cd776aadca",
                            "lessThan": "3cc283fd16fba72e2cefe3a6f48d7a36b0438900",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "2d9a93b4902be6a5504b5941dd15e9cd776aadca",
                            "lessThan": "3bb5849675ae1d592929798a2b37ea450879c855",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "2d9a93b4902be6a5504b5941dd15e9cd776aadca",
                            "lessThan": "2e7ef287f07c74985f1bf2858bedc62bd9ebf155",
                            "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/ipv6/mcast.c"
                    ],
                    "versions": [
                        {
                            "version": "5.13",
                            "status": "affected"
                        },
                        {
                            "version": "0",
                            "lessThan": "5.13",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "5.15.148",
                            "lessThanOrEqual": "5.15.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.1.75",
                            "lessThanOrEqual": "6.1.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.6.14",
                            "lessThanOrEqual": "6.6.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.7.2",
                            "lessThanOrEqual": "6.7.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.8",
                            "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": "5.13",
                                    "versionEndExcluding": "5.15.148"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "5.13",
                                    "versionEndExcluding": "6.1.75"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "5.13",
                                    "versionEndExcluding": "6.6.14"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "5.13",
                                    "versionEndExcluding": "6.7.2"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "5.13",
                                    "versionEndExcluding": "6.8"
                                }
                            ]
                        }
                    ]
                }
            ],
            "references": [
                {
                    "url": "https://git.kernel.org/stable/c/75ddcd741d2a30696f5893bc71a9d28f4ef22311"
                },
                {
                    "url": "https://git.kernel.org/stable/c/62b3387beef11738eb6ce667601a28fa089fa02c"
                },
                {
                    "url": "https://git.kernel.org/stable/c/380540bb06bb1d1b12bdc947d1b8f56cda6b5663"
                },
                {
                    "url": "https://git.kernel.org/stable/c/3cc283fd16fba72e2cefe3a6f48d7a36b0438900"
                },
                {
                    "url": "https://git.kernel.org/stable/c/3bb5849675ae1d592929798a2b37ea450879c855"
                },
                {
                    "url": "https://git.kernel.org/stable/c/2e7ef287f07c74985f1bf2858bedc62bd9ebf155"
                }
            ],
            "title": "ipv6: mcast: fix data-race in ipv6_mc_down / mld_ifc_work",
            "x_generator": {
                "engine": "bippy-1.2.0"
            }
        },
        "adp": [
            {
                "providerMetadata": {
                    "orgId": "af854a3a-2127-422b-91ae-364da2661108",
                    "shortName": "CVE",
                    "dateUpdated": "2024-08-02T00:07:19.693Z"
                },
                "title": "CVE Program Container",
                "references": [
                    {
                        "url": "https://git.kernel.org/stable/c/62b3387beef11738eb6ce667601a28fa089fa02c",
                        "tags": [
                            "x_transferred"
                        ]
                    },
                    {
                        "url": "https://git.kernel.org/stable/c/380540bb06bb1d1b12bdc947d1b8f56cda6b5663",
                        "tags": [
                            "x_transferred"
                        ]
                    },
                    {
                        "url": "https://git.kernel.org/stable/c/3cc283fd16fba72e2cefe3a6f48d7a36b0438900",
                        "tags": [
                            "x_transferred"
                        ]
                    },
                    {
                        "url": "https://git.kernel.org/stable/c/3bb5849675ae1d592929798a2b37ea450879c855",
                        "tags": [
                            "x_transferred"
                        ]
                    },
                    {
                        "url": "https://git.kernel.org/stable/c/2e7ef287f07c74985f1bf2858bedc62bd9ebf155",
                        "tags": [
                            "x_transferred"
                        ]
                    }
                ]
            },
            {
                "metrics": [
                    {
                        "other": {
                            "type": "ssvc",
                            "content": {
                                "timestamp": "2024-08-27T14:55:41.665799Z",
                                "id": "CVE-2024-26631",
                                "options": [
                                    {
                                        "Exploitation": "none"
                                    },
                                    {
                                        "Automatable": "no"
                                    },
                                    {
                                        "Technical Impact": "partial"
                                    }
                                ],
                                "role": "CISA Coordinator",
                                "version": "2.0.3"
                            }
                        }
                    }
                ],
                "title": "CISA ADP Vulnrichment",
                "providerMetadata": {
                    "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
                    "shortName": "CISA-ADP",
                    "dateUpdated": "2024-08-27T14:55:52.147Z"
                }
            }
        ]
    }
}