{"id":"CVE-2026-99039","title":"memstick: core: wait for request completion before freeing card","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nmemstick: core: wait for request completion before freeing card\n\nIn memstick_alloc_card() and memstick_set_rw_addr(),\nwait_for_completion_timeout() is used to wait for …","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= baf8532a147d5b76681ce040e2c8f25a3f0e718d < c3ab92542475d59ae685cbb294e70ca4d0ba38e9","Linux >= baf8532a147d5b76681ce040e2c8f25a3f0e718d < 810580cf60edc75c9891c2de3225e4cda78e4d9f","Linux >= baf8532a147d5b76681ce040e2c8f25a3f0e718d < f2795c50144d528dabc2cf2fd53c0f0c63a823a1","Linux >= baf8532a147d5b76681ce040e2c8f25a3f0e718d < 3af81770e2011c6ac7bb597a4af2e4f3591f928c","Linux >= baf8532a147d5b76681ce040e2c8f25a3f0e718d < aa0a37b5024d921e96ac4f8f487c8bfbf1f1a582","Linux 2.6.25"],"published":"2026-10-23","updated":"2026-10-23","sourceUpdated":"2026-10-23T12:21:57.421Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-99039","references":[{"url":"https://git.kernel.org/stable/c/c3ab92542475d59ae685cbb294e70ca4d0ba38e9"},{"url":"https://git.kernel.org/stable/c/810580cf60edc75c9891c2de3225e4cda78e4d9f"},{"url":"https://git.kernel.org/stable/c/f2795c50144d528dabc2cf2fd53c0f0c63a823a1"},{"url":"https://git.kernel.org/stable/c/3af81770e2011c6ac7bb597a4af2e4f3591f928c"},{"url":"https://git.kernel.org/stable/c/aa0a37b5024d921e96ac4f8f487c8bfbf1f1a582"}],"tags":["cve.org"],"ingestedAt":"2026-10-23T13:24:55.528Z","slug":"CVE-2026-99039","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nmemstick: core: wait for request completion before freeing card\n\nIn memstick_alloc_card() and memstick_set_rw_addr(),\nwait_for_completion_timeout() is used to wait for device identification\nand address configuration requests to complete.\n\nThe memstick subsystem does not provide an abort or cancellation\ncallback in struct memstick_host for in-flight requests. If\nwait_for_completion_timeout() expires (for instance, when a USB transfer\nor command retry is delayed), memstick_alloc_card() returns an error and\nfrees the memstick_dev structure via kfree(card).\n\nHowever, the host controller driver (such as rtsx_usb_ms) is still\nrunning the request asynchronously in worker context. When the transfer\neventually finishes, the driver writes into host->req->data, which\npoints to memory inside the already freed card structure. This leads to\na KASAN slab-use-after-free write:\n\n  BUG: KASAN: slab-use-after-free in ms_read_bytes+0x8fe/0x990\n  Write of size 1 at addr ffff88813c188079 by task kworker/1:5/5239\n  Workqueue: events rtsx_usb_ms_handle_req\n  Call Trace:\n   ms_read_bytes+0x8fe/0x990 drivers/memstick/host/rtsx_usb_ms.c:450\n   rtsx_usb_ms_issue_cmd drivers/memstick/host/rtsx_usb_ms.c:477 [inline]\n   rtsx_usb_ms_handle_req+0x557/0x1a00 drivers/memstick/host/rtsx_usb_ms.c:531\n   process_one_work+0xac7/0x1b10 kernel/workqueue.c:3396\n   worker_thread+0x5ef/0xe50 kernel/workqueue.c:3560\n   kthread+0x373/0x450 kernel/kthread.c:436\n\n  Allocated by task 1662:\n   memstick_alloc_card drivers/memstick/core/memstick.c:383 [inline]\n   memstick_check+0x2c1/0x10d0 drivers/memstick/core/memstick.c:452\n   process_one_work+0xac7/0x1b10 kernel/workqueue.c:3396\n\n  Freed by task 1662:\n   kfree+0x20c/0x650 mm/slub.c:6792\n   memstick_alloc_card drivers/memstick/core/memstick.c:420 [inline]\n   memstick_check+0x72b/0x10d0 drivers/memstick/core/memstick.c:452\n   process_one_work+0xac7/0x1b10 kernel/workqueue.c:3396\n\nHost controller drivers (rtsx_usb_ms, jmb38x_ms, tifm_ms, r592) already\nimplement their own hardware and bus timeouts, and callers in\nmspro_block and ms_block already rely on wait_for_completion()\nunconditionally.\n\nReplace wait_for_completion_timeout() with wait_for_completion() in\nmemstick_set_rw_addr() and memstick_alloc_card() so that the card\nstructure is never freed while an asynchronous request is in flight.\n\n## Affected\n\n- `Linux >= baf8532a147d5b76681ce040e2c8f25a3f0e718d < c3ab92542475d59ae685cbb294e70ca4d0ba38e9`\n- `Linux >= baf8532a147d5b76681ce040e2c8f25a3f0e718d < 810580cf60edc75c9891c2de3225e4cda78e4d9f`\n- `Linux >= baf8532a147d5b76681ce040e2c8f25a3f0e718d < f2795c50144d528dabc2cf2fd53c0f0c63a823a1`\n- `Linux >= baf8532a147d5b76681ce040e2c8f25a3f0e718d < 3af81770e2011c6ac7bb597a4af2e4f3591f928c`\n- `Linux >= baf8532a147d5b76681ce040e2c8f25a3f0e718d < aa0a37b5024d921e96ac4f8f487c8bfbf1f1a582`\n- `Linux 2.6.25`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}