CVE-2026-90044

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.

Affected Software

References

• https://git.kernel.org/stable/c/153b5ecd29ed055562400bc17c91df3fd869b0ce
• https://git.kernel.org/stable/c/4a2fb2d12b87b43724230abb52a1440617c7b6cc
• https://git.kernel.org/stable/c/b5f0e80a03e87bd932487e03248eae3ba3ed7b45
• https://git.kernel.org/stable/c/e78dcb1f7ec271449c54984dc90c62a5ba272de7