{"id":"CVE-2026-89688","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-89688","summary":"nfsd: drop the stateid, not the stateowner, on seqid_op replay retry","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: drop the stateid, not the stateowner, on seqid_op replay retry\n\nIn nfs4_preprocess_seqid_op() the stateid is obtained from\nnfsd4_lookup_stateid(), which holds a reference on the nfs4_stid\n(sc_count) but takes no reference on the stateowner. openlockstateid()\nmerely casts that stid and likewise takes no reference.\n\nWhen nfsd4_cstate_assign_replay() returns -EAGAIN (the replay owner is\nbeing torn down, RP_UNHASHED) it has not taken a stateowner reference on\nthat path. The error handling nevertheless called\nnfs4_put_stateowner(stp->st_stateowner), dropping an so_count reference\nthe function never acquired -- risking a stateowner refcount underflow and\nuse-after-free -- while leaking the sc_count reference held on the stid.\nThe leaked stid reference can also stall a concurrent\nnfsd4_close_open_stateid() waiting for sc_count to drop.\n\nDrop the reference actually held -- the stid -- before retrying. The\nstateowner stays alive through the reference held by the stid. This mirrors\nthe open path in nfsd4_process_open1(), where the put balances a reference\nthat path explicitly holds on the stateowner.","published":"2026-09-11T19:46:09.322Z","modified":"2026-09-14T03:46:27.766219875Z","cvss":{"score":9.8,"severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"Linux","name":"Kernel","fixedVersion":"6.12.109"}],"fix":null,"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/00843074d9b84824552c9679d423d29500ca5de0"},{"type":"WEB","url":"https://git.kernel.org/stable/c/5e4627d3513e60accfce9d5f4c7fa95251ef93d6"},{"type":"WEB","url":"https://git.kernel.org/stable/c/69ed78b6b947c9257213164678b4edf17533093b"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f7cb90ddc021747fc9abfd4cf5252d425fd34eec"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89688.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89688"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-09-14T03:46:27.766219875Z"}}