usb: gadget: at91_udc: drain polled-VBUS timer/work before udc is freed
In the Linux kernel, the following vulnerability has been resolved: usb: gadget: at91_udc: drain polled-VBUS timer/work before udc is freed In polled-VBUS mode (board.vbus_pin && board.vbus_polled), probe arms a self-restarting cycle: at91_vbus_timer() schedules vbus_timer_work, and at91_vbus_timer_work() calls at91_vbus_update() and re-arms the timer via mod_timer(). Both recover the same udc through container_of and dereference it on every iteration. Neither teardown path cancels this cycle. udc is devm-allocated, so it is freed after at91udc_remove() returns, and is likewise freed when probe fails and devres runs. A timer callback or work item that is pending or running at either point dereferences the freed udc. Add at91_udc_shutdown_vbus_timer() and call it from at91udc_remove() and from the usb_add_gadget_udc() failure path in probe; the remaining probe error paths fail before the timer is armed. timer_shutdown_sync() waits for a running callback and clears timer->function, which makes the work handler's mod_timer() a permanent no-op; cancel_work_sync() then drains any pending or running work whose re-arm attempt now does nothing. The timer must be shut down first, since cancelling the work alone would let the timer re-queue it. The guard mirrors probe: in IRQ mode the timer and work_struct are never initialized. This does not require a fault; a normal driver unbind can interleave with an already queued work item. This issue was found by an in-house static analysis tool
CVE-2026-89738
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-89738
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "4037242c4f5ff77afe61bf07ca1e8a99490219e5",
"lessThan": "723d73b245843d4fff4c3f42e857c78c2b2d414e",
"versionType": "git"
},
{
"status": "affected",
"version": "4037242c4f5ff77afe61bf07ca1e8a99490219e5",
"lessThan": "a2a602cb1e28d76a5398cec3fa21b0110385f501",
"versionType": "git"
},
{
"status": "affected",
"version": "4037242c4f5ff77afe61bf07ca1e8a99490219e5",
"lessThan": "51a311eb97e91ce1aed3005cb71ccb2e30f8cce8",
"versionType": "git"
},
{
"status": "affected",
"version": "4037242c4f5ff77afe61bf07ca1e8a99490219e5",
"lessThan": "557ef547d49ff5e6026a4d39bdd3113bd81d7688",
"versionType": "git"
},
{
"status": "affected",
"version": "4037242c4f5ff77afe61bf07ca1e8a99490219e5",
"lessThan": "c27d13ce4bab80fbdf6523928071b6c24b37606c",
"versionType": "git"
}
],
"programFiles": [
"drivers/usb/gadget/udc/at91_udc.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "2.6.36"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "2.6.36",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.6.160",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.109",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.50",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.2.4",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"drivers/usb/gadget/udc/at91_udc.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-89738
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #46715 · Revision 1
- Added to Heist Feed
- Publisher date