CVE-2026-98305 (GCVE-0-2026-98305)
Vulnerability from cvelistv5
Published
2026-10-06 08:46
Modified
2026-10-19 09:17
Summary
In the Linux kernel, the following vulnerability has been resolved: net: dsa: mxl862xx: disable the stats poll on teardown mxl862xx_setup() arms the stats poll before mxl862xx_setup_mdio(), and nothing stops it until dsa_register_switch() has returned an error to mxl862xx_probe(). DSA frees the dsa_port list before it returns, so a poll that fires once .setup or a later step of dsa_tree_setup() has failed walks freed ports. On shutdown the user ports stay registered, and the WORK_STOPPED flag test in mxl862xx_get_stats64() is not atomic with the cancel in mxl862xx_shutdown(), so a re-arm that read the flag before it was set queues the poll after cancel_delayed_work_sync() has returned. Arm the poll once .setup has succeeded and stop it from a .teardown op, which DSA calls on unregister and after a failed registration, in both cases before it frees the ports. Use disable_delayed_work_sync() there and in shutdown(): it drains a running poll as the cancel did and turns every later attempt to queue the work into a no-op, so the re-arm cannot bring the poll back. remove() and the probe error path only set WORK_STOPPED, which crc_err_work tests before it walks the ports.
Impacted products
Vendor Product Version
Linux Linux Version: a21d33a5265f0b31d935a8b9b2b6faefb5185911
Version: a21d33a5265f0b31d935a8b9b2b6faefb5185911
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/dsa/mxl862xx/mxl862xx.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "97df811a11d4f76bc2ffe67b6bf730263f56c668",
              "status": "affected",
              "version": "a21d33a5265f0b31d935a8b9b2b6faefb5185911",
              "versionType": "git"
            },
            {
              "lessThan": "9e92ad4630f5dd1838ce6bbe6b1bd2c73d34de36",
              "status": "affected",
              "version": "a21d33a5265f0b31d935a8b9b2b6faefb5185911",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/dsa/mxl862xx/mxl862xx.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "7.1"
            },
            {
              "lessThan": "7.1",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.8",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.8",
                  "versionStartIncluding": "7.1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3",
                  "versionStartIncluding": "7.1",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: dsa: mxl862xx: disable the stats poll on teardown\n\nmxl862xx_setup() arms the stats poll before mxl862xx_setup_mdio(), and\nnothing stops it until dsa_register_switch() has returned an error to\nmxl862xx_probe(). DSA frees the dsa_port list before it returns, so a\npoll that fires once .setup or a later step of dsa_tree_setup() has\nfailed walks freed ports. On shutdown the user ports stay registered,\nand the WORK_STOPPED flag test in mxl862xx_get_stats64() is not atomic\nwith the cancel in mxl862xx_shutdown(), so a re-arm that read the flag\nbefore it was set queues the poll after cancel_delayed_work_sync() has\nreturned.\n\nArm the poll once .setup has succeeded and stop it from a .teardown op,\nwhich DSA calls on unregister and after a failed registration, in both\ncases before it frees the ports. Use disable_delayed_work_sync() there\nand in shutdown(): it drains a running poll as the cancel did and turns\nevery later attempt to queue the work into a no-op, so the re-arm\ncannot bring the poll back. remove() and the probe error path only set\nWORK_STOPPED, which crc_err_work tests before it walks the ports."
        }
      ],
      "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 - The racing input is local: reading /proc/net/dev or RTM_GETLINK calls dsa_user_get_stats64() -\u003e mxl862xx_get_stats64(), which re-queues priv-\u003estats_work. No packet from a remote peer feeds the bug; it is a teardown-ordering error in mxl862xx_setup()/remove()/shutdown().\nAC:L - placeholder\nPR:L - Any unprivileged local user can read interface statistics on the switch\u0027s user ports, and that read is the attacker\u0027s side of the race (the schedule_delayed_work() call in mxl862xx_get_stats64()). No capability check stands in the way.\nUI:N - No victim action such as opening a file or mounting media is needed. The attacker\u0027s part is only repeated stats reads; the teardown event is covered under AC.\nS:U - The freed dsa_port objects and the devm-freed mxl862xx_priv are kernel memory, and the impact stays within the kernel\u0027s own security authority.\nC:H - mxl862xx_stats_work_fn() walks the ds-\u003eports list after dsa_switch_release_ports() has run kfree(dp). It reads dp-\u003eindex from freed memory and writes counters into priv-\u003eports[].stats. A use-after-free like this can be turned into a memory read primitive.\nI:H - On remove, a re-armed stats_work sits inside the devm-freed mxl862xx_priv. When its timer fires, the workqueue uses the work_struct and its func pointer from memory that may have been reallocated, which allows control-flow hijack. The stats poll also writes into freed memory.\nA:H - Walking freed dsa_port entries or running a work item from freed priv memory causes a kernel oops or panic. In the shutdown case, the poll keeps reaching the switch after mxl862xx_host_shutdown(), which can also crash the system during reboot."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T09:17:16.045Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/97df811a11d4f76bc2ffe67b6bf730263f56c668"
        },
        {
          "url": "https://git.kernel.org/stable/c/9e92ad4630f5dd1838ce6bbe6b1bd2c73d34de36"
        }
      ],
      "title": "net: dsa: mxl862xx: disable the stats poll on teardown",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-98305",
    "datePublished": "2026-10-06T08:46:02.190Z",
    "dateReserved": "2026-09-25T10:25:14.338Z",
    "dateUpdated": "2026-10-19T09:17:16.045Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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