GHSA-Q9QR-5342-RRW2
Vulnerability from github – Published: 2026-06-25 09:31 – Updated: 2026-06-28 09:31In the Linux kernel, the following vulnerability has been resolved:
VFS: fix possible failure to unlock in nfsd4_create_file()
atomic_create() in fs/namei.c drops the reference to the dentry when it returns an error. This behaviour was imported into dentry_create() so that it will drop the reference if an error is returned from atomic_create(), though not if vfs_create() returns an error (in the case where ->atomic_create is not supported).
The caller - nfsd4_create_file() - is made aware of this by checking path->dentry, which will either be a counted reference to a dentry, or an error pointer.
However the change to use start_creating()/end_creating() (which landed shortly before the dentry_create() change landed, though was likely developed around the same time) means that nfsd4_create_file() needs a valid dentry so that it can unlock the parent.
The net result is that if NFSD exports a filesystem which uses ->atomic_create, and if a call to ->atomic_create returns an error, then nfsd4_create_file() will pass an error pointer to end_creating() and the parent will not be unlocked.
Fix this by changing dentry_create() to make sure path->dentry is always a valid dentry, never an error-pointer. The actual error is already returned a different way.
Note that if ->atomic_create() returns a different dentry (which may not be possible in practice) we are guaranteed (because it is only ever provided by d_spliace_alias()) that it will have the same d_parent and so it will have the same effect when passed to end_creating().
{
"affected": [],
"aliases": [
"CVE-2026-53244"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-06-25T09:16:42Z",
"severity": "HIGH"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nVFS: fix possible failure to unlock in nfsd4_create_file()\n\natomic_create() in fs/namei.c drops the reference to the dentry\nwhen it returns an error.\nThis behaviour was imported into dentry_create() so that it\nwill drop the reference if an error is returned from atomic_create(),\nthough not if vfs_create() returns an error (in the case where\n-\u003eatomic_create is not supported).\n\nThe caller - nfsd4_create_file() - is made aware of this by checking\npath-\u003edentry, which will either be a counted reference to a dentry, or\nan error pointer.\n\nHowever the change to use start_creating()/end_creating() (which landed\nshortly before the dentry_create() change landed, though was likely\ndeveloped around the same time) means that nfsd4_create_file() *needs* a\nvalid dentry so that it can unlock the parent.\n\nThe net result is that if NFSD exports a filesystem which uses\n-\u003eatomic_create, and if a call to -\u003eatomic_create returns an error, then\nnfsd4_create_file() will pass an error pointer to end_creating()\nand the parent will not be unlocked.\n\nFix this by changing dentry_create() to make sure path-\u003edentry is always\na valid dentry, never an error-pointer. The actual error is already\nreturned a different way.\n\nNote that if -\u003eatomic_create() returns a different dentry (which may not\nbe possible in practice) we are guaranteed (because it is only ever\nprovided by d_spliace_alias()) that it will have the same d_parent and\nso it will have the same effect when passed to end_creating().",
"id": "GHSA-q9qr-5342-rrw2",
"modified": "2026-06-28T09:31:46Z",
"published": "2026-06-25T09:31:22Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-53244"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/e824bbd4d224cce4b5fb59cc9dcd3447fe0b7e44"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/ee1f40759a50b1800c98c1c369afd5b3e44ad987"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
]
}
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