VulnerabilityPublished 23 Oct 2026

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

Source GCVE Database

Authoritative record:CVE-2026-99039· High

Not known to be exploited · fixed in f2795c50144d528dabc2cf2fd53c0f0c63a823a1 : patch Linux kernel soon.

Data as of 26 Oct 2026, 14:05 UTC

Severity

High

Rated by Threat Radar · CVSS not yet scored by NVD

EPSS: 0.1% chance of exploitation in 30 days – higher than 6% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in f2795c50144d528dabc2cf2fd53c0f0c63a823a1, c3ab92542475d59ae685cbb294e70ca4d0ba38e9, aa0a37b5024d921e96ac4f8f487c8bfbf1f1a582 +2

Exploitation evidence

Disclosed: evidence found.
CVE published 23 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

ghsa-r8cv-6pg4-74wg

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ baf8532a147d5b76681ce040e2c8f25a3f0e718d, < f2795c50144d528dabc2cf2fd53c0f0c63a823a1	Fixed in f2795c50144d528dabc2cf2fd53c0f0c63a823a1
LinuxLinux	Affected ≥ baf8532a147d5b76681ce040e2c8f25a3f0e718d, < c3ab92542475d59ae685cbb294e70ca4d0ba38e9	Fixed in c3ab92542475d59ae685cbb294e70ca4d0ba38e9
LinuxLinux	Affected ≥ baf8532a147d5b76681ce040e2c8f25a3f0e718d, < aa0a37b5024d921e96ac4f8f487c8bfbf1f1a582	Fixed in aa0a37b5024d921e96ac4f8f487c8bfbf1f1a582
LinuxLinux	Affected ≥ baf8532a147d5b76681ce040e2c8f25a3f0e718d, < 810580cf60edc75c9891c2de3225e4cda78e4d9f	Fixed in 810580cf60edc75c9891c2de3225e4cda78e4d9f
LinuxLinux	Affected ≥ baf8532a147d5b76681ce040e2c8f25a3f0e718d, < 3af81770e2011c6ac7bb597a4af2e4f3591f928c	Fixed in 3af81770e2011c6ac7bb597a4af2e4f3591f928c
LinuxLinux	Affected =2.6.25	Fixed in–

Description

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.

References

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