CVE-2026-99039memstick: core: wait for request completion before freeing card

In the Linux kernel, the following vulnerability has been resolved: memstick: core: wait for request completion before freeing card In memstick_alloc_card() and memstick_set_rw_addr(), wait_for_completion_timeout() is used to wait for device identification and address configuration requests to complete. The memstick subsystem does not provide an abort or cancellation callback in struct memstick_host for in-flight requests. If wait_for_completion_timeout() expires (for instance, when a USB transfer or command retry is delayed), memstick_alloc_card() returns an error and frees the memstick_dev structure via kfree(card). However, the host controller driver (such as rtsx_usb_ms) is still running the request asynchronously in worker context. When the transfer eventually finishes, the driver writes into host->req->data, which points to memory inside the already freed card structure. This leads to a KASAN slab-use-after-free write: BUG: KASAN: slab-use-after-free in ms_read_bytes+0x8fe/0x990 Write of size 1 at addr ffff88813c188079 by task kworker/1:5/5239 Workqueue: events rtsx_usb_ms_handle_req Call Trace: ms_read_bytes+0x8fe/0x990 drivers/memstick/host/rtsx_usb_ms.c:450 rtsx_usb_ms_issue_cmd drivers/memstick/host/rtsx_usb_ms.c:477 [inline] rtsx_usb_ms_handle_req+0x557/0x1a00 drivers/memstick/host/rtsx_usb_ms.c:531 process_one_work+0xac7/0x1b10 kernel/workqueue.c:3396 worker_thread+0x5ef/0xe50 kernel/workqueue.c:3560 kthread+0x373/0x450 kernel/kthread.c:436 Allocated by task 1662: memstick_alloc_card drivers/memstick/core/memstick.c:383 [inline] memstick_check+0x2c1/0x10d0 drivers/memstick/core/memstick.c:452 process_one_work+0xac7/0x1b10 kernel/workqueue.c:3396 Freed by task 1662: kfree+0x20c/0x650 mm/slub.c:6792 memstick_alloc_card drivers/memstick/core/memstick.c:420 [inline] memstick_check+0x72b/0x10d0 drivers/memstick/core/memstick.c:452 process_one_work+0xac7/0x1b10 kernel/workqueue.c:3396 Host controller drivers (rtsx_usb_ms, jmb38x_ms, tifm_ms, r592) already implement their own hardware and bus timeouts, and callers in mspro_block and ms_block already rely on wait_for_completion() unconditionally. Replace wait_for_completion_timeout() with wait_for_completion() in memstick_set_rw_addr() and memstick_alloc_card() so that the card structure is never freed while an asynchronous request is in flight.

CVSS

Not yet scored

Weakness (CWE)

Not given

Known exploited

Not in CISA's KEV catalog

EPSS (exploitation in the next 30 days)

Not loaded for this CVE

Assigned by

Linux

NVD analysis

Received

Record last updated

Oct 23, 2026

First seen by InfoSec Signals

Oct 23, 2026

The CVE record on cve.org · NVD's entry

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