CVE-2026-72113 (GCVE-0-2026-72113)
Vulnerability from cvelistv5
Published
2026-08-15 05:52
Modified
2026-08-19 16:35
Summary
In the Linux kernel, the following vulnerability has been resolved: can: bcm: add missing device refcount for CAN filter removal sashiko-bot remarked a problem with a concurrent device unregistration in isotp.c which also is present in the bcm.c code. A former fix for raw.c commit c275a176e4b6 ("can: raw: add missing refcount for memory leak fix") introduced a netdevice_tracker which solves the issue for bcm.c too. bcm_release(), bcm_delete_rx_op() and bcm_notifier() relied on dev_get_by_index(ifindex) to re-find the device for an rx_op before unregistering its filter. If a concurrent NETDEV_UNREGISTER has already unlisted the device from the ifindex table, that lookup fails and can_rx_unregister() is silently skipped, leaving a stale CAN filter pointing at the soon-to-be-freed bcm_op/socket. Hold a netdev_hold()/netdev_put() tracked reference on op->rx_reg_dev from the moment the rx filter is registered in bcm_rx_setup() until it is unregistered in bcm_rx_unreg(), and use that reference directly in bcm_release() and bcm_delete_rx_op() instead of re-looking the device up by ifindex.
Impacted products
Vendor Product Version
Linux Linux Version: ffd980f976e7fd666c2e61bf8ab35107efd11828
Version: ffd980f976e7fd666c2e61bf8ab35107efd11828
Version: ffd980f976e7fd666c2e61bf8ab35107efd11828
Version: ffd980f976e7fd666c2e61bf8ab35107efd11828
Version: ffd980f976e7fd666c2e61bf8ab35107efd11828
Version: ffd980f976e7fd666c2e61bf8ab35107efd11828
Version: ffd980f976e7fd666c2e61bf8ab35107efd11828
Version: ffd980f976e7fd666c2e61bf8ab35107efd11828
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/can/bcm.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "versionType": "git"
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              "versionType": "git"
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            {
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            {
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            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/can/bcm.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2.6.25"
            },
            {
              "lessThan": "2.6.25",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.265",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.216",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.183",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.148",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.101",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.42",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.265",
                  "versionStartIncluding": "2.6.25",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.216",
                  "versionStartIncluding": "2.6.25",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.183",
                  "versionStartIncluding": "2.6.25",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.148",
                  "versionStartIncluding": "2.6.25",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.101",
                  "versionStartIncluding": "2.6.25",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.42",
                  "versionStartIncluding": "2.6.25",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.5",
                  "versionStartIncluding": "2.6.25",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "2.6.25",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncan: bcm: add missing device refcount for CAN filter removal\n\nsashiko-bot remarked a problem with a concurrent device unregistration\nin isotp.c which also is present in the bcm.c code. A former fix for raw.c\ncommit c275a176e4b6 (\"can: raw: add missing refcount for memory leak fix\")\nintroduced a netdevice_tracker which solves the issue for bcm.c too.\n\nbcm_release(), bcm_delete_rx_op() and bcm_notifier() relied on\ndev_get_by_index(ifindex) to re-find the device for an rx_op before\nunregistering its filter. If a concurrent NETDEV_UNREGISTER has already\nunlisted the device from the ifindex table, that lookup fails and\ncan_rx_unregister() is silently skipped, leaving a stale CAN filter\npointing at the soon-to-be-freed bcm_op/socket.\n\nHold a netdev_hold()/netdev_put() tracked reference on op-\u003erx_reg_dev\nfrom the moment the rx filter is registered in bcm_rx_setup() until it\nis unregistered in bcm_rx_unreg(), and use that reference directly in\nbcm_release() and bcm_delete_rx_op() instead of re-looking the device\nup by ifindex."
        }
      ],
      "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 syscalls (socket/sendmsg/close) on PF_CAN/CAN_BCM and concurrent netdev teardown via netlink; the flaw is in local filter cleanup, not remote IP packet handling.\nAC:L - An attacker can reliably win the race by concurrently closing the BCM socket or issuing RX_DELETE while deleting the bound vcan/CAN interface from the same user namespace.\nPR:L - BCM sockets need no special capability, and CAP_NET_ADMIN for creating/deleting vcan interfaces is obtainable by unprivileged users via user namespaces (unshare -Urn).\nUI:N - No victim interaction is required; exploitation is fully attacker-driven through BCM socket setup, concurrent netdev removal, and subsequent CAN traffic to hit the stale filter.\nS:U - Impact is confined to kernel memory corruption and privilege escalation within the same security authority; it does not cross VM, container, or IOMMU boundaries.\nC:H - Stale CAN filters leave a use-after-free on freed bcm_op structures; bcm_rx_handler dereferences attacker-influenced freed memory, enabling arbitrary kernel memory disclosure via heap grooming.\nI:H - The UAF in bcm_rx_handler provides write primitives over freed bcm_op fields (timers, frame buffers, socket pointers), enabling control-flow hijacking and arbitrary kernel code execution.\nA:H - Accessing the freed bcm_op from bcm_rx_handler causes kernel oops/panic; UAF is inherently crash-prone even before full exploitation."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-19T16:35:58.404Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/bd5232663524e94cc5aad861dca11e3db8e2ab6f"
        },
        {
          "url": "https://git.kernel.org/stable/c/ee8b36d0faca08f35b889b6e9aa850695e5b8ba9"
        },
        {
          "url": "https://git.kernel.org/stable/c/dcaee869913c7210cd47ed0a8f27349d7bdcdb7b"
        },
        {
          "url": "https://git.kernel.org/stable/c/84aa4807816e405c1bf87114fc63e06d244281ef"
        },
        {
          "url": "https://git.kernel.org/stable/c/633bda66fbf309f5de5e1ad6defe8e6b1d77a20f"
        },
        {
          "url": "https://git.kernel.org/stable/c/b024c21c9066f6957b7d4a8f2037e4b000c5e041"
        },
        {
          "url": "https://git.kernel.org/stable/c/04d23061bbf18d5d81022eb21e9d32e99d24468d"
        },
        {
          "url": "https://git.kernel.org/stable/c/d59948293ea34b6337ce2b5febab8510de70048c"
        }
      ],
      "title": "can: bcm: add missing device refcount for CAN filter removal",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-72113",
    "datePublished": "2026-08-15T05:52:54.001Z",
    "dateReserved": "2026-08-09T03:40:39.906Z",
    "dateUpdated": "2026-08-19T16:35:58.404Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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