CVE-2026-31578 (GCVE-0-2026-31578)

Vulnerability from cvelistv5 – Published: 2026-04-24 14:42 – Updated: 2026-04-24 14:42
VLAI?
Title
media: as102: fix to not free memory after the device is registered in as102_usb_probe()
Summary
In the Linux kernel, the following vulnerability has been resolved: media: as102: fix to not free memory after the device is registered in as102_usb_probe() In as102_usb driver, the following race condition occurs: ``` CPU0 CPU1 as102_usb_probe() kzalloc(); // alloc as102_dev_t .... usb_register_dev(); fd = sys_open("/path/to/dev"); // open as102 fd .... usb_deregister_dev(); .... kfree(); // free as102_dev_t .... sys_close(fd); as102_release() // UAF!! as102_usb_release() kfree(); // DFB!! ``` When a USB character device registered with usb_register_dev() is later unregistered (via usb_deregister_dev() or disconnect), the device node is removed so new open() calls fail. However, file descriptors that are already open do not go away immediately: they remain valid until the last reference is dropped and the driver's .release() is invoked. In as102, as102_usb_probe() calls usb_register_dev() and then, on an error path, does usb_deregister_dev() and frees as102_dev_t right away. If userspace raced a successful open() before the deregistration, that open FD will later hit as102_release() --> as102_usb_release() and access or free as102_dev_t again, occur a race to use-after-free and double-free vuln. The fix is to never kfree(as102_dev_t) directly once usb_register_dev() has succeeded. After deregistration, defer freeing memory to .release(). In other words, let release() perform the last kfree when the final open FD is closed.
Severity ?
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 582fbecb3756330006fe1950762412a68c2cacd2 (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 09e9206008b887aa553733bd915d73131071a086 (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 2eeae47a438694408189138048a786be99954032 (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 7e5aedf6059cba2a669d86caeaf5a51f33ec85a1 (git)
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    Linux Linux Unaffected: 6.12.83 , ≤ 6.12.* (semver)
Unaffected: 6.18.24 , ≤ 6.18.* (semver)
Unaffected: 6.19.14 , ≤ 6.19.* (semver)
Unaffected: 7.0.1 , ≤ 7.0.* (semver)
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{
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      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/media/usb/as102/as102_usb_drv.c"
          ],
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          "vendor": "Linux",
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          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmedia: as102: fix to not free memory after the device is registered in as102_usb_probe()\n\nIn as102_usb driver, the following race condition occurs:\n```\n\t\tCPU0\t\t\t\t\t\tCPU1\nas102_usb_probe()\n  kzalloc(); // alloc as102_dev_t\n  ....\n  usb_register_dev();\n\t\t\t\t\t\tfd = sys_open(\"/path/to/dev\"); // open as102 fd\n\t\t\t\t\t\t....\n  usb_deregister_dev();\n  ....\n  kfree(); // free as102_dev_t\n  ....\n\t\t\t\t\t\tsys_close(fd);\n\t\t\t\t\t\t  as102_release() // UAF!!\n\t\t\t\t\t\t    as102_usb_release()\n\t\t\t\t\t\t      kfree(); // DFB!!\n```\n\nWhen a USB character device registered with usb_register_dev() is later\nunregistered (via usb_deregister_dev() or disconnect), the device node is\nremoved so new open() calls fail. However, file descriptors that are\nalready open do not go away immediately: they remain valid until the last\nreference is dropped and the driver\u0027s .release() is invoked.\n\nIn as102, as102_usb_probe() calls usb_register_dev() and then, on an\nerror path, does usb_deregister_dev() and frees as102_dev_t right away.\nIf userspace raced a successful open() before the deregistration, that\nopen FD will later hit as102_release() --\u003e as102_usb_release() and access\nor free as102_dev_t again, occur a race to use-after-free and\ndouble-free vuln.\n\nThe fix is to never kfree(as102_dev_t) directly once usb_register_dev()\nhas succeeded. After deregistration, defer freeing memory to .release().\n\nIn other words, let release() perform the last kfree when the final open\nFD is closed."
        }
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      "providerMetadata": {
        "dateUpdated": "2026-04-24T14:42:09.519Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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          "url": "https://git.kernel.org/stable/c/2eeae47a438694408189138048a786be99954032"
        },
        {
          "url": "https://git.kernel.org/stable/c/7e5aedf6059cba2a669d86caeaf5a51f33ec85a1"
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      ],
      "title": "media: as102: fix to not free memory after the device is registered in as102_usb_probe()",
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-31578",
    "datePublished": "2026-04-24T14:42:09.519Z",
    "dateReserved": "2026-03-09T15:48:24.119Z",
    "dateUpdated": "2026-04-24T14:42:09.519Z",
    "state": "PUBLISHED"
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  }
}


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