# CVE-2025-40094: usb: gadget: f\_acm: Refactor bind path to use \_\_free()

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Published: 2025-10-30 · Updated: 2026-08-05

## Affected

- Linux: version range not reported
- Linux: 2.6.27

## Description

In the Linux kernel, the following vulnerability has been resolved: usb: gadget: f_acm: Refactor bind path to use __free() After an bind/unbind cycle, the acm->notify_req is left stale. If a subsequent bind fails, the unified error label attempts to free this stale request, leading to a NULL pointer dereference when accessing ep->ops->free_request. Refactor the error handling in the bind path to use the __free() automatic cleanup mechanism. Unable to handle kernel NULL pointer dereference at virtual address 0000000000000020 Call trace: usb_ep_free_request+0x2c/0xec gs_free_req+0x30/0x44 acm_bind+0x1b8/0x1f4 usb_add_function+0xcc/0x1f0 configfs_composite_bind+0x468/0x588 gadget_bind_driver+0x104/0x270 really_probe+0x190/0x374 __driver_probe_device+0xa0/0x12c driver_probe_device+0x3c/0x218 __device_attach_driver+0x14c/0x188 bus_for_each_drv+0x10c/0x168 __device_attach+0xfc/0x198 device_initial_probe+0x14/0x24 bus_probe_device+0x94/0x11c device_add+0x268/0x48c usb_add_gadget+0x198/0x28c dwc3_gadget_init+0x700/0x858 __dwc3_set_mode+0x3cc/0x664 process_scheduled_works+0x1d8/0x488 worker_thread+0x244/0x334 kthread+0x114/0x1bc ret_from_fork+0x10/0x20

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
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## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/c5d116862dd3ed162d079738a5ebddf9fceea850
- https://git.kernel.org/stable/c/2b1546f7c5fc6c44555a8e7a2b34229d1dcd2175
- https://git.kernel.org/stable/c/e348d18fb0124b662cfefb3001733b49da428215
- https://git.kernel.org/stable/c/201a66d8e6630762e760e1d78f1d149da1691e7b
- https://git.kernel.org/stable/c/c4301e4dd6b32faccb744f1c2320e64235b68d3b
- https://git.kernel.org/stable/c/47b2116e54b4a854600341487e8b55249e926324

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Page: https://cve.now/CVE-2025-40094
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