CVE-2026-89669

/// Technical 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 l

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References