GHSA-2W4F-22FV-V9W4
Vulnerability from github – Published: 2026-08-15 06:32 – Updated: 2026-08-15 06:32In the Linux kernel, the following vulnerability has been resolved:
mmc: vub300: fix use-after-free on probe failure
The vub300 driver lifetime-manages its controller state using vub300->kref, with vub300_delete() freeing the mmc host when the last reference is dropped. The probe error path after the inactivity timer has been armed still bypasses that lifetime rule, however, and falls through to mmc_free_host() directly if mmc_add_host() fails.
The race window is between arming the inactivity timer and reaching the probe error unwind after mmc_add_host() fails:
probe thread timer/workqueue
------------ ---------------
kref_init(&vub300->kref) ref = 1
kref_get(&vub300->kref) ref = 2, timer ref
add_timer(inactivity_timer) fires after one second
|
| race window
|<---------------------------------------------------->
|
mmc_add_host(mmc)
inactivity timer fires
vub300_queue_dead_work()
kref_get() ref = 3
queue_work(deadwork)
mmc_add_host() fails
timer_delete_sync()
mmc_free_host(mmc)
frees vub300
deadwork runs
use-after-free
The inactivity timeout is one second, so this would require mmc_add_host() to both fail and take more than one second to do so. This is unlikely to happen in practice, but the error path is still wrong.
timer_delete_sync() only waits for the timer callback itself. It does not flush deadwork that the callback may already have queued. As a result, queued deadwork can still hold a kref while the probe error path directly frees the backing mmc host, including the vub300 storage.
Fix this by using the same lifetime mechanism as disconnect. Clear vub300->interface so that the timer callback and any queued deadwork return early and drop their references, then drop the initial probe reference and return without falling through to err_free_host.
{
"affected": [],
"aliases": [
"CVE-2026-72073"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-08-15T06:21:17Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nmmc: vub300: fix use-after-free on probe failure\n\nThe vub300 driver lifetime-manages its controller state using\nvub300-\u003ekref, with vub300_delete() freeing the mmc host when the last\nreference is dropped. The probe error path after the inactivity timer has\nbeen armed still bypasses that lifetime rule, however, and falls through\nto mmc_free_host() directly if mmc_add_host() fails.\n\nThe race window is between arming the inactivity timer and reaching the\nprobe error unwind after mmc_add_host() fails:\n\n probe thread timer/workqueue\n ------------ ---------------\n kref_init(\u0026vub300-\u003ekref) ref = 1\n kref_get(\u0026vub300-\u003ekref) ref = 2, timer ref\n add_timer(inactivity_timer) fires after one second\n |\n | race window\n |\u003c----------------------------------------------------\u003e\n |\n mmc_add_host(mmc)\n inactivity timer fires\n vub300_queue_dead_work()\n kref_get() ref = 3\n queue_work(deadwork)\n mmc_add_host() fails\n timer_delete_sync()\n mmc_free_host(mmc)\n frees vub300\n deadwork runs\n use-after-free\n\nThe inactivity timeout is one second, so this would require\nmmc_add_host() to both fail and take more than one second to do so. This\nis unlikely to happen in practice, but the error path is still wrong.\n\ntimer_delete_sync() only waits for the timer callback itself. It does\nnot flush deadwork that the callback may already have queued. As a\nresult, queued deadwork can still hold a kref while the probe error path\ndirectly frees the backing mmc host, including the vub300 storage.\n\nFix this by using the same lifetime mechanism as disconnect. Clear\nvub300-\u003einterface so that the timer callback and any queued deadwork\nreturn early and drop their references, then drop the initial probe\nreference and return without falling through to err_free_host.",
"id": "GHSA-2w4f-22fv-v9w4",
"modified": "2026-08-15T06:32:11Z",
"published": "2026-08-15T06:32:11Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-72073"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/5b82af744e06cd741938c3da54fdbe564a7e52d9"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/618cf6b139503ec18ef93ffd663396aaf99b763a"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/a3b5f242997a3be7404112fd48784881560aea57"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
| Author | Source | Type | Date | Other |
|---|
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The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.