GHSA-R3WC-V3P2-877P
Vulnerability from github – Published: 2026-09-11 21:31 – Updated: 2026-09-11 21:31In the Linux kernel, the following vulnerability has been resolved:
NFS/localio: fix ref leak on nfs_uuid_add_file failure
When nfs_uuid_add_file() races with nfs_uuid_put() tearing down uuid->net, it returns -ENXIO without publishing nfl->nfs_uuid via rcu_assign_pointer(). nfs_open_local_fh() then enters its error branch and only releases the slot's file ref and its paired net ref plus its own entry-time net ref, while the close path is a no-op:
nfs_close_local_fh()
nfs_uuid = rcu_dereference(nfl->nfs_uuid);
if (!nfs_uuid) { rcu_read_unlock(); return; } /* always */
nfsd_open_local_fh() returns localio holding a caller-owned +1 nfsd_file reference (from nfsd_file_get() after nfsd_file_acquire_local()) and an entry-time nfsd_net reference (from its first nfsd_net_try_get()) embedded as nf->nf_net. Both are leaked on the failure path, pinning one nfsd_file (and the underlying struct file, dentry, inode) and one nfsd_net_ref per occurrence, which blocks nfsd_net and netns teardown.
Fix by releasing the caller-owned file ref and its net ref through the existing helper, using a stack-local RCU pointer so the helper can xchg it out, then returning -ENXIO so callers do not dereference a localio whose slot has been cleared:
struct nfsd_file __rcu *tmp = RCU_INITIALIZER(localio);
nfs_to_nfsd_file_put_local(pnf);
nfs_to_nfsd_file_put_local(&tmp);
localio = ERR_PTR(-ENXIO);
The trailing nfs_to_nfsd_net_put(net) continues to release the outer net ref, so all three nfsd_net_try_get() increments are balanced on the error branch.
{
"affected": [],
"aliases": [
"CVE-2026-89715"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-09-11T20:19:58Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nNFS/localio: fix ref leak on nfs_uuid_add_file failure\n\nWhen nfs_uuid_add_file() races with nfs_uuid_put() tearing down\nuuid-\u003enet, it returns -ENXIO without publishing nfl-\u003enfs_uuid via\nrcu_assign_pointer(). nfs_open_local_fh() then enters its error\nbranch and only releases the slot\u0027s file ref and its paired net\nref plus its own entry-time net ref, while the close path is a\nno-op:\n\n nfs_close_local_fh()\n nfs_uuid = rcu_dereference(nfl-\u003enfs_uuid);\n if (!nfs_uuid) { rcu_read_unlock(); return; } /* always */\n\nnfsd_open_local_fh() returns localio holding a caller-owned +1\nnfsd_file reference (from nfsd_file_get() after\nnfsd_file_acquire_local()) and an entry-time nfsd_net reference\n(from its first nfsd_net_try_get()) embedded as nf-\u003enf_net. Both\nare leaked on the failure path, pinning one nfsd_file (and the\nunderlying struct file, dentry, inode) and one nfsd_net_ref per\noccurrence, which blocks nfsd_net and netns teardown.\n\nFix by releasing the caller-owned file ref and its net ref through\nthe existing helper, using a stack-local RCU pointer so the helper\ncan xchg it out, then returning -ENXIO so callers do not\ndereference a localio whose slot has been cleared:\n\n struct nfsd_file __rcu *tmp = RCU_INITIALIZER(localio);\n\n nfs_to_nfsd_file_put_local(pnf);\n nfs_to_nfsd_file_put_local(\u0026tmp);\n localio = ERR_PTR(-ENXIO);\n\nThe trailing nfs_to_nfsd_net_put(net) continues to release the\nouter net ref, so all three nfsd_net_try_get() increments are\nbalanced on the error branch.",
"id": "GHSA-r3wc-v3p2-877p",
"modified": "2026-09-11T21:31:37Z",
"published": "2026-09-11T21:31:37Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-89715"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/5215e734bf7cba18237155f8cb2a0accb60ca339"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/9f59b05423ed381f8cdeaaae4bd6778adcb6865c"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/ca018c19e0ba38975e5ddc3ef8117d5b734313aa"
}
],
"schema_version": "1.4.0",
"severity": []
}
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