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.