CVE-2026-89694

About vulnerability

In the Linux kernel, the following vulnerability has been resolved:

nfsd: check client ownership when cancelling a copy-notify stateid

On the OFFLOAD_CANCEL path (clp != NULL), manage_cpntf_state() freed the target cpntf state without checking ownership. The lookup key st->si_opaque.so_id is allocated cyclically (guessable) and the embedded clientid is the fixed per-net nn->s2s_cp_cl_id, so any authenticated NFSv4.2 client could cancel and free another client’s copy-notify stateid.

Compare the creating clientid recorded in state->cp_p_clid against the requesting client’s cl_clientid and return nfserr_bad_stateid on a mismatch instead of freeing the entry.

Affected product:

AlmaLinux 9.2 ESU , Amazon Linux 2 ELS , Debian 10 ELS , Debian 11 ELS , TuxCare 9.6 ESU , TuxCare 9.8 ESU

Affected packages:

linux @ 4.19.0 (+5 more)

Live-patch status from KernelCare for each operating system.