CVE-2026-89669: Linux Vulnerability (CVSS 9.8)

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.

Metrics

CVSS 3.1

9.8/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

0.61%

47.2th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

Vendor	Product	Versions
Linux	Linux	>= 624322f1adc58acd0b69f77a6ddc764207e97241, < 863b6e995665472f2af5be2436a874ab6a9e5ac6; >= 624322f1adc58acd0b69f77a6ddc764207e97241, < d18d36395d973ef7372c8e6724970585f75b5c0b; >= 624322f1adc58acd0b69f77a6ddc764207e97241, < 4415a692346a39fdb647cbd717eda510159aaf55; >= 624322f1adc58acd0b69f77a6ddc764207e97241, < 9caad13b7cfe9ccb90cc405ac77335800e086595; >= 624322f1adc58acd0b69f77a6ddc764207e97241, < e08a3dcaca0505f861e344a387f37f94d95dbdc2; >= 624322f1adc58acd0b69f77a6ddc764207e97241, < a4d7fedcaaf33e60a01e53eafca9041ef966212f; >= 624322f1adc58acd0b69f77a6ddc764207e97241, < 4cdef96892f4fa6e70c405b6e8f2fd6972f3b64b; >= 624322f1adc58acd0b69f77a6ddc764207e97241, < 129643893b79f8a3c6b72045f933fbab5ee424ca
Linux	Linux	5.6

References

Timeline

Published: Sep 11, 2026
Last Modified: Sep 14, 2026
Status: Received

Frequently Asked Questions

What is CVE-2026-89669?

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.

How severe is CVE-2026-89669?

CVE-2026-89669 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 0.61% probability of exploitation in the next 30 days.

How do I fix CVE-2026-89669?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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