FKIE_CVE-2026-97480

Vulnerability from fkie_nvd - Published: 2026-09-24 17:17 - Updated: 2026-09-24 17:17
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: tty: serial: 8250: protect against NULL uart->port.dev in register serial8250_register_8250_port() conditionally copies uart->port.dev from up->port.dev only when up->port.dev is non-NULL: if (up->port.dev) { uart->port.dev = up->port.dev; ... } So if both the existing uart slot and up have a NULL ->dev, uart->port.dev remains NULL. The very next ACPI companion check then dereferences it unconditionally: if (!has_acpi_companion(uart->port.dev)) { has_acpi_companion() reads dev->fwnode without a NULL guard (include/linux/acpi.h), so this NULL-derefs the kernel for the remaining no-dev case rather than just skipping the mctrl_gpio_init() initialisation as intended. smatch flags the inconsistency: drivers/tty/serial/8250/8250_core.c:767 serial8250_register_8250_port() error: 'uart->port.dev' could be null (see line 719) Guard the call with a NULL check so register continues to work for callers that legitimately have no parent device (legacy non-OF/non-ACPI registrations). No functional change for callers that pass a non-NULL ->dev.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/5cbab666721d974bfe033a12045d808936deaefd
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/941c9f84c9b6310f7aaa1c8c785dcc634ee33050
Impacted products
Vendor Product Version
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{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/tty/serial/8250/8250_core.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "5cbab666721d974bfe033a12045d808936deaefd",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "941c9f84c9b6310f7aaa1c8c785dcc634ee33050",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "6.18.53",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/tty/serial/8250/8250_core.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.53",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntty: serial: 8250: protect against NULL uart-\u003eport.dev in register\n\nserial8250_register_8250_port() conditionally copies uart-\u003eport.dev\nfrom up-\u003eport.dev only when up-\u003eport.dev is non-NULL:\n\n\tif (up-\u003eport.dev) {\n\t\tuart-\u003eport.dev = up-\u003eport.dev;\n\t\t...\n\t}\n\nSo if both the existing uart slot and up have a NULL -\u003edev,\nuart-\u003eport.dev remains NULL. The very next ACPI companion check\nthen dereferences it unconditionally:\n\n\tif (!has_acpi_companion(uart-\u003eport.dev)) {\n\nhas_acpi_companion() reads dev-\u003efwnode without a NULL guard\n(include/linux/acpi.h), so this NULL-derefs the kernel for the\nremaining no-dev case rather than just skipping the\nmctrl_gpio_init() initialisation as intended.\n\nsmatch flags the inconsistency:\n\n  drivers/tty/serial/8250/8250_core.c:767\n  serial8250_register_8250_port() error: \u0027uart-\u003eport.dev\u0027 could be\n  null (see line 719)\n\nGuard the call with a NULL check so register continues to work\nfor callers that legitimately have no parent device (legacy\nnon-OF/non-ACPI registrations).\n\nNo functional change for callers that pass a non-NULL -\u003edev."
    }
  ],
  "id": "CVE-2026-97480",
  "lastModified": "2026-09-24T17:17:25.467",
  "metrics": {},
  "published": "2026-09-24T17:17:25.467",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/5cbab666721d974bfe033a12045d808936deaefd"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/941c9f84c9b6310f7aaa1c8c785dcc634ee33050"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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