NFSD: Prevent client use-after-free during blocked-lock reaping
In the Linux kernel, the following vulnerability has been resolved: NFSD: Prevent client use-after-free during blocked-lock reaping A bare lock owner -- its only remaining reference a blocked lock on nn->blocked_locks_lru -- holds a raw pointer to its nfs4_client but no reference keeping the client alive. When the per-net laundromat reaps such a lock, freeing the nbl drops the owner reference held through flc_owner, and the final nfs4_put_stateowner() takes the client's cl_lock. Because the laundromat detaches the nbl first, __destroy_client() no longer finds it, so a concurrent force_expire_client() can free the client before nfs4_put_stateowner() runs, dereferencing cl_lock in freed memory. Pin the client with cl_rpc_users before dropping nn->blocked_locks_lock, and skip clients already expiring, whose blocked locks __destroy_client() frees while holding an owner reference. Take nn->client_lock outside nn->blocked_locks_lock. Every other site holds nn->blocked_locks_lock as a leaf, acquiring no further lock, so placing nn->client_lock outside it cannot form a lock-order cycle.
CVE-2026-90036
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-90036
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "7919d0a27f1e7cb324e023776aa1cbff00f1ee7b",
"lessThan": "0d53a47c913d0bce3b5ec35c28cbcca4d015f33d",
"versionType": "git"
},
{
"status": "affected",
"version": "7919d0a27f1e7cb324e023776aa1cbff00f1ee7b",
"lessThan": "7081224a59a0ca4edcd62c068588f4d900199a18",
"versionType": "git"
},
{
"status": "affected",
"version": "7919d0a27f1e7cb324e023776aa1cbff00f1ee7b",
"lessThan": "cd489b03587378645fe0d20142a33f1ed60bac98",
"versionType": "git"
},
{
"status": "affected",
"version": "7919d0a27f1e7cb324e023776aa1cbff00f1ee7b",
"lessThan": "6fedb2eaff77554ca7a0deffd2e8bc0d6e8b38b0",
"versionType": "git"
},
{
"status": "affected",
"version": "7919d0a27f1e7cb324e023776aa1cbff00f1ee7b",
"lessThan": "9026932ac8be4d0ae01db47f23619a98cc57b671",
"versionType": "git"
}
],
"programFiles": [
"fs/nfsd/nfs4state.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "4.9"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "4.9",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.6.160",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.111",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.51",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.2.5",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"fs/nfsd/nfs4state.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-90036
Source reference:
/cveMetadata/cveId
Publisher severity
critical
Source reference: /containers/cna/metrics
- Event
- #48585 · Revision 1
- Added to Heist Feed
- Publisher date