nfsd: provide locking for v4_end_grace
In the Linux kernel, the following vulnerability has been resolved: nfsd: provide locking for v4_end_grace Writing to v4_end_grace can race with server shutdown and result in memory being accessed after it was freed - reclaim_str_hashtbl in particularly. We cannot hold nfsd_mutex across the nfsd4_end_grace() call as that is held while client_tracking_op->init() is called and that can wait for an upcall to nfsdcltrack which can write to v4_end_grace, resulting in a deadlock. nfsd4_end_grace() is also called by the landromat work queue and this doesn't require locking as server shutdown will stop the work and wait for it before freeing anything that nfsd4_end_grace() might access. However, we must be sure that writing to v4_end_grace doesn't restart the work item after shutdown has already waited for it. For this we add a new flag protected with nn->client_lock. It is set only while it is safe to make client tracking calls, and v4_end_grace only schedules work while the flag is set with the spinlock held. So this patch adds a nfsd_net field "client_tracking_active" which is set as described. Another field "grace_end_forced", is set when v4_end_grace is written. After this is set, and providing client_tracking_active is set, the laundromat is scheduled. This "grace_end_forced" field bypasses other checks for whether the grace period has finished. This resolves a race which can result in use-after-free.
CVE-2026-22980
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-2026-22980
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": "7f5ef2e900d9462bf9cffaf6bb246ed87a20a6d6",
"lessThan": "ca97360860eb02e3ae4ba42c19b439a0fcecbf06",
"versionType": "git"
},
{
"status": "affected",
"version": "7f5ef2e900d9462bf9cffaf6bb246ed87a20a6d6",
"lessThan": "e8bfa2401d4c51eca6e48e9b33c798828ca9df61",
"versionType": "git"
},
{
"status": "affected",
"version": "7f5ef2e900d9462bf9cffaf6bb246ed87a20a6d6",
"lessThan": "34eb22836e0cdba093baac66599d68c4cd245a9d",
"versionType": "git"
},
{
"status": "affected",
"version": "7f5ef2e900d9462bf9cffaf6bb246ed87a20a6d6",
"lessThan": "06600719d0f7a723811c45e4d51f5b742f345309",
"versionType": "git"
},
{
"status": "affected",
"version": "7f5ef2e900d9462bf9cffaf6bb246ed87a20a6d6",
"lessThan": "ba4811c8b433bfa681729ca42cc62b6034f223b0",
"versionType": "git"
},
{
"status": "affected",
"version": "7f5ef2e900d9462bf9cffaf6bb246ed87a20a6d6",
"lessThan": "53f07d095e7e680c5e4569a55a019f2c0348cdc6",
"versionType": "git"
},
{
"status": "affected",
"version": "7f5ef2e900d9462bf9cffaf6bb246ed87a20a6d6",
"lessThan": "2857bd59feb63fcf40fe4baf55401baea6b4feb4",
"versionType": "git"
}
],
"programFiles": [
"fs/nfsd/netns.h",
"fs/nfsd/nfs4state.c",
"fs/nfsd/nfsctl.c",
"fs/nfsd/state.h"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "3.18"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "3.18",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.10.248",
"versionType": "semver",
"lessThanOrEqual": "5.10.*"
},
{
"status": "unaffected",
"version": "5.15.198",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.161",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.121",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.66",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.6",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "6.19",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"fs/nfsd/netns.h",
"fs/nfsd/nfs4state.c",
"fs/nfsd/nfsctl.c",
"fs/nfsd/state.h"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-22980
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #39717 · Revision 1
- Added to Heist Feed
- Publisher date