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CVE PROGRAM SOURCE RECORD7.8 High

CVE-2026-89738

usb: gadget: at91_udc: drain polled-VBUS timer/work before udc is freed

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Status
Published
Published
Updated
Assigning organization
Linux

Description

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.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Linux Linux

Default version status: unaffected

  • 4037242c4f5ff77afe61bf07ca1e8a99490219e5 to < 2440ce54b8c4c8aa6963c181eb56164a466fbe1caffected
  • 4037242c4f5ff77afe61bf07ca1e8a99490219e5 to < 1674e34fe61ad3f5585dc833ba6bb6522912e6a5affected
  • 4037242c4f5ff77afe61bf07ca1e8a99490219e5 to < 723d73b245843d4fff4c3f42e857c78c2b2d414eaffected
  • 4037242c4f5ff77afe61bf07ca1e8a99490219e5 to < a2a602cb1e28d76a5398cec3fa21b0110385f501affected
  • 4037242c4f5ff77afe61bf07ca1e8a99490219e5 to < 51a311eb97e91ce1aed3005cb71ccb2e30f8cce8affected
  • 4037242c4f5ff77afe61bf07ca1e8a99490219e5 to < 557ef547d49ff5e6026a4d39bdd3113bd81d7688affected
  • 4037242c4f5ff77afe61bf07ca1e8a99490219e5 to < c27d13ce4bab80fbdf6523928071b6c24b37606caffected

Linux Linux

Default version status: affected

  • 2.6.36affected
  • 0 to < 2.6.36unaffected
  • 5.15.224 to ≤ 5.15.*unaffected
  • 6.1.191 to ≤ 6.1.*unaffected
  • 6.6.160 to ≤ 6.6.*unaffected
  • 6.12.109 to ≤ 6.12.*unaffected
  • 6.18.50 to ≤ 6.18.*unaffected
  • 7.2.4 to ≤ 7.2.*unaffected
  • 7.3 to ≤ *unaffected

References