# CVE-2026-89669

## Summary

- **CVE ID:** CVE-2026-89669
- **Severity:** CRITICAL
- **CVSS Score:** 9.8 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H)
- **CWE:** N/A
- **Published:** Sep 11, 2026
- **Last Modified:** Sep 14, 2026

## 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.

## Affected Products

- Linux — Linux (624322f1adc58acd0b69f77a6ddc764207e97241)
- Linux — Linux (5.6)
- Linux — Linux (0)
- Linux — Linux (6.12.109)
- Linux — Linux (6.18.50)
- Linux — Linux (7.2.4)
- Linux — Linux (7.3-rc1)
- Linux — Linux (5.10.270)
- Linux — Linux (5.15.221)
- Linux — Linux (6.1.188)
- Linux — Linux (6.6.157)

## References

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

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.68%
- **EPSS Percentile:** 50.9

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-18._