CVE-2026-72125 (GCVE-0-2026-72125)
Vulnerability from cvelistv5
Published
2026-08-15 05:53
Modified
2026-08-19 16:36
Summary
In the Linux kernel, the following vulnerability has been resolved: can: isotp: fix use-after-free race with concurrent NETDEV_UNREGISTER isotp_release() looked up the bound network device via dev_get_by_index() using the stored ifindex. During device unregistration the device is unlisted from the ifindex hash before the NETDEV_UNREGISTER notifier chain runs, so a concurrent isotp_release() could find no device, skip can_rx_unregister() entirely, and still proceed to free the socket. Since isotp_release() had already removed itself from the isotp notifier list at that point, isotp_notify() would never get a chance to clean up either, leaving a stale CAN filter that keeps pointing at the freed socket. Fix this the same way raw.c already does: hold a tracked reference to the bound net_device in the socket (so->dev/so->dev_tracker) from bind() onward instead of re-resolving it from the ifindex, and serialize bind()/release() with rtnl_lock() so that so->dev is always consistent with what the NETDEV_UNREGISTER notifier sees. so->dev stays valid regardless of ifindex-hash unlisting, and is only ever cleared by whichever of isotp_release()/isotp_notify() gets there first, so the filter is always removed exactly once. isotp_bind() now rejects a (re)bind with -EAGAIN while so->[tx|rx].state isn't ISOTP_IDLE yet, so a timer left running by a prior NETDEV_UNREGISTER can't act on a newly bound so->ifindex. Both checks share the same lock_sock() section, so there is no window in which a concurrent isotp_notify() clearing so->bound could be missed.
Impacted products
Vendor Product Version
Linux Linux Version: e057dd3fc20ffb3d7f150af46542a51b59b90127
Version: e057dd3fc20ffb3d7f150af46542a51b59b90127
Version: e057dd3fc20ffb3d7f150af46542a51b59b90127
Version: e057dd3fc20ffb3d7f150af46542a51b59b90127
Version: e057dd3fc20ffb3d7f150af46542a51b59b90127
Version: e057dd3fc20ffb3d7f150af46542a51b59b90127
Version: e057dd3fc20ffb3d7f150af46542a51b59b90127
Version: e057dd3fc20ffb3d7f150af46542a51b59b90127
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
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          "programFiles": [
            "net/can/isotp.c"
          ],
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          "product": "Linux",
          "programFiles": [
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          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "version": "5.10"
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              "version": "0",
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              "version": "5.10.265",
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            },
            {
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              "version": "5.15.216",
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              "version": "6.1.183",
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              "version": "6.6.148",
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            },
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              "status": "unaffected",
              "version": "6.12.101",
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            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.40",
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              "status": "unaffected",
              "version": "7.1.5",
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            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.265",
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                  "vulnerable": true
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                  "vulnerable": true
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                  "versionEndExcluding": "7.2",
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              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncan: isotp: fix use-after-free race with concurrent NETDEV_UNREGISTER\n\nisotp_release() looked up the bound network device via dev_get_by_index()\nusing the stored ifindex. During device unregistration the device is\nunlisted from the ifindex hash before the NETDEV_UNREGISTER notifier\nchain runs, so a concurrent isotp_release() could find no device, skip\ncan_rx_unregister() entirely, and still proceed to free the socket.\nSince isotp_release() had already removed itself from the isotp\nnotifier list at that point, isotp_notify() would never get a chance to\nclean up either, leaving a stale CAN filter that keeps pointing at the\nfreed socket.\n\nFix this the same way raw.c already does: hold a tracked reference to\nthe bound net_device in the socket (so-\u003edev/so-\u003edev_tracker) from\nbind() onward instead of re-resolving it from the ifindex, and\nserialize bind()/release() with rtnl_lock() so that so-\u003edev is always\nconsistent with what the NETDEV_UNREGISTER notifier sees. so-\u003edev\nstays valid regardless of ifindex-hash unlisting, and is only ever\ncleared by whichever of isotp_release()/isotp_notify() gets there\nfirst, so the filter is always removed exactly once.\n\nisotp_bind() now rejects a (re)bind with -EAGAIN while so-\u003e[tx|rx].state\nisn\u0027t ISOTP_IDLE yet, so a timer left running by a prior\nNETDEV_UNREGISTER can\u0027t act on a newly bound so-\u003eifindex. Both checks\nshare the same lock_sock() section, so there is no window in which a\nconcurrent isotp_notify() clearing so-\u003ebound could be missed."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - Exploitation requires local AF_CAN ISO-TP socket operations (socket/bind/close) racing NETDEV_UNREGISTER on the bound CAN interface; stale-filter UAF is triggered via local frame injection or an existing bound interface, not a remote IP/network service.\nAC:L - The attacker controls both sides of the race by concurrently closing the ISO-TP socket and unregistering the bound CAN device (e.g., vcan create/delete with CAP_NET_ADMIN in a user namespace), and can retry until the stale RX filter is left on a freed socket.\nPR:L - No init-namespace root is required: any local user can open CAN_ISOTP sockets, and CAP_NET_ADMIN obtainable in user namespaces suffices to create/delete vcan and drive the unregister path used in automotive/embedded ISO-TP (UDS) deployments.\nUI:N - No victim interaction is needed; the use-after-free is triggered by the attacker\u0027s own concurrent close()/NETDEV_UNREGISTER operations and subsequent CAN frames sent to the bound IDs.\nS:U - Impact is kernel heap corruption and potential privilege escalation within the same OS security boundary; it does not inherently cross VM, container, or IOMMU isolation boundaries.\nC:H - A stale can_rx filter keeps calling isotp_rcv()/isotp_rcv_echo() with a freed isotp_sock, enabling reads of reallocated slab contents through socket state, sock_queue_rcv_skb(), and protocol parsing on attacker-influenced memory.\nI:H - The UAF path performs extensive writes to freed socket state (RX/TX buffers, timers, generation counters) and can emit CAN traffic, providing primitives for heap shaping and control-flow hijack rather than a crash-only fault.\nA:H - Use-after-free in softirq CAN receive callbacks commonly causes kernel oops/panic from dereferencing or writing freed isotp_sock/timer state, even before reliable exploitation."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-19T16:36:23.877Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/f311bbb29bb06aaab69ba45a6e4b11323d20b8f9"
        },
        {
          "url": "https://git.kernel.org/stable/c/8e018f4335590460ebcf0c2b493ed38ba1a35204"
        },
        {
          "url": "https://git.kernel.org/stable/c/33b9cd9245e2a4b800f99ed1cc53d64960614152"
        },
        {
          "url": "https://git.kernel.org/stable/c/0b811c4bbe3ec9ad611e90a540fe8b51b3bb8a96"
        },
        {
          "url": "https://git.kernel.org/stable/c/43884dc7963beef2328f507f4fe680bdc173eb80"
        },
        {
          "url": "https://git.kernel.org/stable/c/7bef39ba76eb7307ed22a50329e0f5776dbeda58"
        },
        {
          "url": "https://git.kernel.org/stable/c/e442b62ba5a7756c17e05a77b32cdd085a2b6138"
        },
        {
          "url": "https://git.kernel.org/stable/c/20bab8b88baac140ca3701116e1d486c7f51e311"
        }
      ],
      "title": "can: isotp: fix use-after-free race with concurrent NETDEV_UNREGISTER",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-72125",
    "datePublished": "2026-08-15T05:53:02.905Z",
    "dateReserved": "2026-08-09T03:40:39.907Z",
    "dateUpdated": "2026-08-19T16:36:23.877Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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