GHSA-FRQJ-GV5H-9HCC
Vulnerability from github – Published: 2026-09-17 18:31 – Updated: 2026-09-17 18:31In the Linux kernel, the following vulnerability has been resolved:
NFSD: Release the export reference when reaping open stateids
nfs4_put_stid() releases the svc_export tracked in nfs4_stid.sc_export, but free_ol_stateid_reaplist() frees open and lock stateids by calling ->sc_free() directly, bypassing that path. An open stateid takes an sc_export reference in nfs4_open() and a lock stateid takes its own in init_lock_stateid(); both reach free_ol_stateid_reaplist() through their normal teardown, the open stateid via release_open_stateid() and the lock stateid via nfsd4_release_lockowner(), each through put_ol_stateid_locked(). The reference is therefore never dropped, pinning the export and blocking unmount for the lifetime of the stateid.
Release sc_export in free_ol_stateid_reaplist() the way nfs4_put_stid() does. ->sc_free() runs once per stateid, and a stateid reaches free_ol_stateid_reaplist() or nfs4_put_stid() but never both, so the reference is dropped exactly once. Revoked stateids reach this path with sc_export already cleared by drop_stid_export(), so they are skipped rather than double-freed.
nfs4_put_stid() itself read sc_export before acquiring cl_lock. drop_stid_export() clears that field and releases the reference under cl_lock, so a concurrent revocation could drop the export in the window between the read and the final put, releasing the same reference twice. Read sc_export while cl_lock is held so the two paths serialize and the reference is released exactly once.
{
"affected": [],
"aliases": [
"CVE-2026-90236"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-09-17T17:17:19Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nNFSD: Release the export reference when reaping open stateids\n\nnfs4_put_stid() releases the svc_export tracked in\nnfs4_stid.sc_export, but free_ol_stateid_reaplist() frees open and\nlock stateids by calling -\u003esc_free() directly, bypassing that path.\nAn open stateid takes an sc_export reference in nfs4_open() and a\nlock stateid takes its own in init_lock_stateid(); both reach\nfree_ol_stateid_reaplist() through their normal teardown, the open\nstateid via release_open_stateid() and the lock stateid via\nnfsd4_release_lockowner(), each through put_ol_stateid_locked().\nThe reference is therefore never dropped, pinning the export and\nblocking unmount for the lifetime of the stateid.\n\nRelease sc_export in free_ol_stateid_reaplist() the way\nnfs4_put_stid() does. -\u003esc_free() runs once per stateid, and a\nstateid reaches free_ol_stateid_reaplist() or nfs4_put_stid() but\nnever both, so the reference is dropped exactly once. Revoked\nstateids reach this path with sc_export already cleared by\ndrop_stid_export(), so they are skipped rather than double-freed.\n\nnfs4_put_stid() itself read sc_export before acquiring cl_lock.\ndrop_stid_export() clears that field and releases the reference\nunder cl_lock, so a concurrent revocation could drop the export in\nthe window between the read and the final put, releasing the same\nreference twice. Read sc_export while cl_lock is held so the two\npaths serialize and the reference is released exactly once.",
"id": "GHSA-frqj-gv5h-9hcc",
"modified": "2026-09-17T18:31:57Z",
"published": "2026-09-17T18:31:57Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-90236"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/6480bd703684ed3f760e9e36c4a699033c0806ae"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/7458727fd7cb79d09e5120b6fecc1ad11cdb0946"
}
],
"schema_version": "1.4.0",
"severity": []
}
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