NFSD: Prevent client use-after-free during delegation revoke
In the Linux kernel, the following vulnerability has been resolved: NFSD: Prevent client use-after-free during delegation revoke A delegation stateid holds only a bare pointer to its owning nfs4_client and does not keep it alive. The client survives its stateids only because __destroy_client() drains cl_delegations and cl_revoked before free_client() runs. nfs4_laundromat() breaks that invariant: it unhashes an expired delegation from cl_delegations, drops deleg_lock, then revoke_delegation() relinks it onto cl_revoked under cl_lock. In that window the delegation is on neither list, so client_has_state() can report no remaining state. Every teardown path first requires cl_rpc_users to be zero, but the laundromat holds no such reference. A client whose recalled delegation has just timed out can therefore reach free_client() while revoke_delegation() is still about to dereference cl_lock, a use-after-free. Pin the client with cl_rpc_users across the revoke so teardown blocks until it completes, then reap the delegation from cl_revoked. A client already expiring reaps its own, so skip it and leave the delegation on del_recall_lru.
CVE-2026-89659
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-2026-89659
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": "3bd64a5ba1719c2bb6cba4493dfd3e23a7653e54",
"lessThan": "94f0c73797c30a35812ffb32d11b8737d245c405",
"versionType": "git"
},
{
"status": "affected",
"version": "3bd64a5ba1719c2bb6cba4493dfd3e23a7653e54",
"lessThan": "0dd276b1324a5e08e83c6f675919946c9f0d61c9",
"versionType": "git"
},
{
"status": "affected",
"version": "3bd64a5ba1719c2bb6cba4493dfd3e23a7653e54",
"lessThan": "3c0a53ee0b442348d8d2286d6960d3f07bb3a3d3",
"versionType": "git"
},
{
"status": "affected",
"version": "3bd64a5ba1719c2bb6cba4493dfd3e23a7653e54",
"lessThan": "2a9d637c2a8fd8ac29ad9b29f28d122ef75c1a56",
"versionType": "git"
},
{
"status": "affected",
"version": "3bd64a5ba1719c2bb6cba4493dfd3e23a7653e54",
"lessThan": "4683ca76b3b7e5808338491c6eb3c20e6b4894d5",
"versionType": "git"
}
],
"programFiles": [
"fs/nfsd/netns.h",
"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": "3.10"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "3.10",
"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": "7.2.4",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"fs/nfsd/netns.h",
"fs/nfsd/nfs4state.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-89659
Source reference:
/cveMetadata/cveId
Publisher severity
critical
Source reference: /containers/cna/metrics
- Event
- #46700 · Revision 1
- Added to Heist Feed
- Publisher date