ipv6: mcast: fix data-race in ipv6_mc_down / mld_ifc_work

{
  "id": "d8c5d337175ab20530c9a6f0788a63aafe0e90f4eaf80ea956acd7b77d8c49d3",
  "url": "https://osv.dev/vulnerability/CVE-2024-26631",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "ipv6: mcast: fix data-race in ipv6_mc_down / mld_ifc_work",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: ipv6: mcast: fix data-race in ipv6_mc_down / mld_ifc_work idev->mc_ifc_count can be written over without proper locking. Originally found by syzbot [1], fix this issue by encapsulating calls to mld_ifc_stop_work() (and mld_gq_stop_work() for good measure) with mutex_lock() and mutex_unlock() accordingly as these functions should only be called with mc_lock per their declarations. [1] BUG: KCSAN: data-race in ipv6_mc_down / mld_ifc_work write to 0xffff88813a80c832 of 1 bytes by task 3771 on cpu 0: mld_ifc_stop_work net/ipv6/mcast.c:1080 [inline] ipv6_mc_down+0x10a/0x280 net/ipv6/mcast.c:2725 addrconf_ifdown+0xe32/0xf10 net/ipv6/addrconf.c:3949 addrconf_notify+0x310/0x980 notifier_call_chain kernel/notifier.c:93 [inline] raw_notifier_call_chain+0x6b/0x1c0 kernel/notifier.c:461 __dev_notify_flags+0x205/0x3d0 dev_change_flags+0xab/0xd0 net/core/dev.c:8685 do_setlink+0x9f6/0x2430 net/core/rtnetlink.c:2916 rtnl_group_changelink net/core/rtnetlink.c:3458 [inline] __rtnl_newlink net/core/rtnetlink.c:3717 [inline] rtnl_newlink+0xbb3/0x1670 net/core/rtnetlink.c:3754 rtnetlink_rcv_msg+0x807/0x8c0 net/core/rtnetlink.c:6558 netlink_rcv_skb+0x126/0x220 net/netlink/af_netlink.c:2545 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:6576 netlink_unicast_kernel net/netlink/af_netlink.c:1342 [inline] netlink_unicast+0x589/0x650 net/netlink/af_netlink.c:1368 netlink_sendmsg+0x66e/0x770 net/netlink/af_netlink.c:1910 ... write to 0xff",
    "evidence": "osv:CVE-2024-26631",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "5.15.148",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.1.75",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.6.14",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.7.2",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2024-26631",
      "aliases": [
        "CVE-2024-26631"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
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              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
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                  "fixed": "75ddcd741d2a30696f5893bc71a9d28f4ef22311"
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              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
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                  "fixed": "62b3387beef11738eb6ce667601a28fa089fa02c"
                },
                {
                  "fixed": "380540bb06bb1d1b12bdc947d1b8f56cda6b5663"
                },
                {
                  "fixed": "3cc283fd16fba72e2cefe3a6f48d7a36b0438900"
                },
                {
                  "fixed": "3bb5849675ae1d592929798a2b37ea450879c855"
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                {
                  "fixed": "2e7ef287f07c74985f1bf2858bedc62bd9ebf155"
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              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2024-26631.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.13.0"
                },
                {
                  "fixed": "5.15.148"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.16.0"
                },
                {
                  "fixed": "6.1.75"
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            },
            {
              "type": "ECOSYSTEM",
              "events": [
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                  "introduced": "6.2.0"
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                {
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            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.7.0"
                },
                {
                  "fixed": "6.7.2"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2024-26631.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:29.333239202Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/2e7ef287f07c74985f1bf2858bedc62bd9ebf155",
        "https://git.kernel.org/stable/c/380540bb06bb1d1b12bdc947d1b8f56cda6b5663",
        "https://git.kernel.org/stable/c/3bb5849675ae1d592929798a2b37ea450879c855",
        "https://git.kernel.org/stable/c/3cc283fd16fba72e2cefe3a6f48d7a36b0438900",
        "https://git.kernel.org/stable/c/62b3387beef11738eb6ce667601a28fa089fa02c",
        "https://git.kernel.org/stable/c/75ddcd741d2a30696f5893bc71a9d28f4ef22311",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/26xxx/CVE-2024-26631.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2024-26631",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/26xxx/CVE-2024-26631.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2024-26631",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 495998,
  "published_at": "2024-03-18T10:07:48.346+00:00"
}