CVE-2026-31578 (GCVE-0-2026-31578)
Vulnerability from cvelistv5
Published
2026-04-24 14:42
Modified
2026-04-27 13:56
Severity ?
VLAI Severity ?
EPSS score ?
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.
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: cd19f7d3e39b3160595d56bb3e3a2bf4f7f4669c Version: cd19f7d3e39b3160595d56bb3e3a2bf4f7f4669c Version: cd19f7d3e39b3160595d56bb3e3a2bf4f7f4669c Version: cd19f7d3e39b3160595d56bb3e3a2bf4f7f4669c Version: cd19f7d3e39b3160595d56bb3e3a2bf4f7f4669c Version: cd19f7d3e39b3160595d56bb3e3a2bf4f7f4669c |
||
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"drivers/media/usb/as102/as102_usb_drv.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
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},
{
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"product": "Linux",
"programFiles": [
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],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
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"version": "3.14"
},
{
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"version": "0",
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{
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"status": "unaffected",
"version": "6.6.136",
"versionType": "semver"
},
{
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"status": "unaffected",
"version": "6.12.83",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.24",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.19.*",
"status": "unaffected",
"version": "6.19.14",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.0.*",
"status": "unaffected",
"version": "7.0.1",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.1-rc1",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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],
"negate": false,
"operator": "OR"
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],
"descriptions": [
{
"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."
}
],
"providerMetadata": {
"dateUpdated": "2026-04-27T13:56:26.085Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/cb8092038e95dc1113a68e63762de40fff61ba71"
},
{
"url": "https://git.kernel.org/stable/c/582fbecb3756330006fe1950762412a68c2cacd2"
},
{
"url": "https://git.kernel.org/stable/c/09e9206008b887aa553733bd915d73131071a086"
},
{
"url": "https://git.kernel.org/stable/c/2eeae47a438694408189138048a786be99954032"
},
{
"url": "https://git.kernel.org/stable/c/7e5aedf6059cba2a669d86caeaf5a51f33ec85a1"
},
{
"url": "https://git.kernel.org/stable/c/8bd29dbe03fc5b0f039ab2395ff37b64236d2f0c"
}
],
"title": "media: as102: fix to not free memory after the device is registered in as102_usb_probe()",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-31578",
"datePublished": "2026-04-24T14:42:09.519Z",
"dateReserved": "2026-03-09T15:48:24.119Z",
"dateUpdated": "2026-04-27T13:56:26.085Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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