GHSA-WRGV-V45W-6GXV
Vulnerability from github – Published: 2026-04-24 15:32 – Updated: 2026-04-24 15:32In 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.
{
"affected": [],
"aliases": [
"CVE-2026-31578"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-04-24T15:16:32Z",
"severity": null
},
"details": "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.",
"id": "GHSA-wrgv-v45w-6gxv",
"modified": "2026-04-24T15:32:34Z",
"published": "2026-04-24T15:32:34Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-31578"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/09e9206008b887aa553733bd915d73131071a086"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/2eeae47a438694408189138048a786be99954032"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/582fbecb3756330006fe1950762412a68c2cacd2"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/7e5aedf6059cba2a669d86caeaf5a51f33ec85a1"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
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