CVE-2026-90044
usb: gadget: f_fs: Fix Use-After-Free in AIO error path
- State
- Published
- Severity
- 7.8 High
- Published
- Sep 16, 2026
- Updated
- Oct 30, 2026
- Reserved
- Sep 11, 2026
Description
In the Linux kernel, the following vulnerability has been resolved:
usb: gadget: f_fs: Fix Use-After-Free in AIO error path
In ffs_epfile_write_iter() and ffs_epfile_read_iter(), when ffs_epfile_io() fails with an error other than -EIOCBQUEUED, the io_data structure (`p`) is freed. However, for AIO operations, the kiocb cancel function was already armed and kiocb->private was set to `p`.
If a concurrent cancel operation (such as sys_io_cancel()) executes after ffs_epfile_io() fails but before the function frees `p`, a Use-After-Free can occur when the cancellation handler accesses the freed pointer.
To securely fix this race condition, we must properly un-arm the cancellation. Invoking `kiocb->ki_complete()` does exactly this by acquiring `ctx->ctx_lock` and safely removing the kiocb from the active sequence. In doing so, it ensures that a parallel io_cancel can no longer discover the kiocb, effectively closing the race window.
We then return -EIOCBQUEUED to notify the VFS layer that the kiocb has been consumed and it should avoid attempting to complete the request again or triggering subsequent completion handlers.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 7.8 High | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H | Linux |
Weaknesses
The record names no weakness.
Affected Products
| Product | Versions |
|---|---|
LinuxLinux |
|
LinuxLinux |
|
References
- https://git.kernel.org/stable/c/922a29e1f8573fd405eea1a73a52112c4e7fcfc4
- https://git.kernel.org/stable/c/0a2f71ccf9c2053de725e9a7922d081f3f3a3804
- https://git.kernel.org/stable/c/b5f0e80a03e87bd932487e03248eae3ba3ed7b45
- https://git.kernel.org/stable/c/153b5ecd29ed055562400bc17c91df3fd869b0ce
- https://git.kernel.org/stable/c/4a2fb2d12b87b43724230abb52a1440617c7b6cc
- https://git.kernel.org/stable/c/e78dcb1f7ec271449c54984dc90c62a5ba272de7
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