NFSD: Guard admin state-revocation walks with NFSD_NET_UP
In the Linux kernel, the following vulnerability has been resolved: NFSD: Guard admin state-revocation walks with NFSD_NET_UP Writing to /proc/fs/nfsd/unlock_filesystem, or sending the NFSD_CMD_UNLOCK_FILESYSTEM or NFSD_CMD_UNLOCK_EXPORT netlink command, walks the NFSv4 client hash tables to revoke open state and cancel async COPY operations. All three handlers gate that walk on nn->nfsd_serv, but a listener added via portlist or netlink listener_set sets nn->nfsd_serv before any nfsd thread starts. nfsd_startup_net() has not yet allocated nn->conf_id_hashtbl, so the walkers dereference a NULL table. A local administrator with CAP_SYS_ADMIN can crash the kernel this way without ever starting the server. nn->nfsd_serv is set when the service is created, which precedes table allocation. NFSD_NET_UP instead brackets the window where the tables are live: set at the end of nfsd_startup_net() and cleared in nfsd_shutdown_net() after they are freed, both under nfsd_mutex. Gating the three unlock paths on NFSD_NET_UP fixes the startup-time NULL dereference while preserving the earlier post-shutdown use-after-free fix.
CVE-2026-90039
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-2026-90039
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": "1ac3629bf012592cb0320e52a1cceb319a05ad17",
"lessThan": "73bf459d696ecf207a9037bf9bb70c51a459469e",
"versionType": "git"
},
{
"status": "affected",
"version": "1ac3629bf012592cb0320e52a1cceb319a05ad17",
"lessThan": "104a51265042b4424085741c963cb858ac29ec0b",
"versionType": "git"
},
{
"status": "affected",
"version": "1ac3629bf012592cb0320e52a1cceb319a05ad17",
"lessThan": "0146467a2fce845cb6629979c3e9c58dd3d3a6a3",
"versionType": "git"
},
{
"status": "affected",
"version": "1ac3629bf012592cb0320e52a1cceb319a05ad17",
"lessThan": "2f3e6638aebc0ab8afb8b4e9816ea9a1cad85378",
"versionType": "git"
}
],
"programFiles": [
"fs/nfsd/nfs4proc.c",
"fs/nfsd/nfs4state.c",
"fs/nfsd/nfsctl.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "6.9"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "6.9",
"versionType": "semver"
},
{
"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/nfs4proc.c",
"fs/nfsd/nfs4state.c",
"fs/nfsd/nfsctl.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-90039
Source reference:
/cveMetadata/cveId
Publisher severity
No explicit severity was provided.
- Event
- #36464 · Revision 1
- Added to Heist Feed
- Publisher date