CVE-2026-64594 (GCVE-0-2026-64594)
Vulnerability from cvelistv5
Published
2026-08-06 07:13
Modified
2026-08-17 04:58
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
usb: gadget: f_fs: initialize reset_work at allocation time
ffs_fs_kill_sb() unconditionally calls cancel_work_sync() on
ffs->reset_work when a functionfs instance is unmounted:
ffs_data_reset(ffs);
cancel_work_sync(&ffs->reset_work);
However ffs->reset_work is only ever initialized via INIT_WORK() in
ffs_func_set_alt() and ffs_func_disable(), and only on the
FFS_DEACTIVATED path. That state is reached solely by ffs_data_closed()
when the instance is mounted with the "no_disconnect" option, so for the
common case (no "no_disconnect", or mounted and unmounted without ever
being deactivated) reset_work is never initialized.
ffs_data_new() allocates the ffs_data with kzalloc_obj() and does not
initialize reset_work, and ffs_data_reset()/ffs_data_clear() do not touch
it either, so reset_work.func is left NULL. cancel_work_sync() on such a
work then trips the WARN_ON(!work->func) guard in __flush_work():
WARNING: kernel/workqueue.c:4301 at __flush_work+0x330/0x360, CPU#3: umount
Call trace:
__flush_work
cancel_work_sync
ffs_fs_kill_sb [usb_f_fs]
deactivate_locked_super
deactivate_super
cleanup_mnt
__cleanup_mnt
task_work_run
exit_to_user_mode_loop
el0_svc
On older kernels cancel_work_sync() on a zero-initialized work struct was
a silent no-op, which hid the missing initialization.
Initialize reset_work once in ffs_data_new() so it is always valid for
the lifetime of the ffs_data, and drop the now-redundant INIT_WORK()
calls from the two deactivation paths.
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: 18d6b32fca3841f7cd9479b4024abd8a9b299281 Version: 18d6b32fca3841f7cd9479b4024abd8a9b299281 Version: 18d6b32fca3841f7cd9479b4024abd8a9b299281 Version: 18d6b32fca3841f7cd9479b4024abd8a9b299281 Version: 18d6b32fca3841f7cd9479b4024abd8a9b299281 Version: 18d6b32fca3841f7cd9479b4024abd8a9b299281 Version: 18d6b32fca3841f7cd9479b4024abd8a9b299281 Version: 18d6b32fca3841f7cd9479b4024abd8a9b299281 |
||
{
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{
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"version": "5.15.212",
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{
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"version": "6.1.178",
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{
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}
],
"cpeApplicability": [
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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\nusb: gadget: f_fs: initialize reset_work at allocation time\n\nffs_fs_kill_sb() unconditionally calls cancel_work_sync() on\nffs-\u003ereset_work when a functionfs instance is unmounted:\n\n\tffs_data_reset(ffs);\n\tcancel_work_sync(\u0026ffs-\u003ereset_work);\n\nHowever ffs-\u003ereset_work is only ever initialized via INIT_WORK() in\nffs_func_set_alt() and ffs_func_disable(), and only on the\nFFS_DEACTIVATED path. That state is reached solely by ffs_data_closed()\nwhen the instance is mounted with the \"no_disconnect\" option, so for the\ncommon case (no \"no_disconnect\", or mounted and unmounted without ever\nbeing deactivated) reset_work is never initialized.\n\nffs_data_new() allocates the ffs_data with kzalloc_obj() and does not\ninitialize reset_work, and ffs_data_reset()/ffs_data_clear() do not touch\nit either, so reset_work.func is left NULL. cancel_work_sync() on such a\nwork then trips the WARN_ON(!work-\u003efunc) guard in __flush_work():\n\n WARNING: kernel/workqueue.c:4301 at __flush_work+0x330/0x360, CPU#3: umount\n Call trace:\n __flush_work\n cancel_work_sync\n ffs_fs_kill_sb [usb_f_fs]\n deactivate_locked_super\n deactivate_super\n cleanup_mnt\n __cleanup_mnt\n task_work_run\n exit_to_user_mode_loop\n el0_svc\n\nOn older kernels cancel_work_sync() on a zero-initialized work struct was\na silent no-op, which hid the missing initialization.\n\nInitialize reset_work once in ffs_data_new() so it is always valid for\nthe lifetime of the ffs_data, and drop the now-redundant INIT_WORK()\ncalls from the two deactivation paths."
}
],
"providerMetadata": {
"dateUpdated": "2026-08-17T04:58:16.410Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/7fe895e0a9651518c4fc082487da770ff9c14c7f"
},
{
"url": "https://git.kernel.org/stable/c/0de6ebbabfbbc9c28350283dc97d8a519d5c6dd7"
},
{
"url": "https://git.kernel.org/stable/c/cb19e54ebe9baf3c3243083ade65c937339ccb7b"
},
{
"url": "https://git.kernel.org/stable/c/d5631081be07f20e764d3cb5c98ac0a1004fba51"
},
{
"url": "https://git.kernel.org/stable/c/c36393b0d14e1e9783888f821ffe29381b8f46dc"
},
{
"url": "https://git.kernel.org/stable/c/69faa3779250df14f51d5084f938a99809546e52"
},
{
"url": "https://git.kernel.org/stable/c/ba1867999dbc4085e6d8c52ac5266005b8b2bf07"
},
{
"url": "https://git.kernel.org/stable/c/3137b243c93982fe3460335e12f9247739766e10"
}
],
"title": "usb: gadget: f_fs: initialize reset_work at allocation time",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-64594",
"datePublished": "2026-08-06T07:13:50.309Z",
"dateReserved": "2026-07-19T15:36:31.799Z",
"dateUpdated": "2026-08-17T04:58:16.410Z",
"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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