CVE-2026-22980 - Vulnerability Details

Vendors	Products
Linux	Linux Kernel

Link	Providers
https://git.kernel.org/stable/c/06600719d0f7a723811c45e4d51f5b742f345309
https://git.kernel.org/stable/c/2857bd59feb63fcf40fe4baf55401baea6b4feb4
https://git.kernel.org/stable/c/34eb22836e0cdba093baac66599d68c4cd245a9d
https://git.kernel.org/stable/c/53f07d095e7e680c5e4569a55a019f2c0348cdc6
https://git.kernel.org/stable/c/ba4811c8b433bfa681729ca42cc62b6034f223b0
https://git.kernel.org/stable/c/ca97360860eb02e3ae4ba42c19b439a0fcecbf06
https://git.kernel.org/stable/c/e8bfa2401d4c51eca6e48e9b33c798828ca9df61

Type	Values Removed	Values Added
Description		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.
Title		nfsd: provide locking for v4_end_grace
First Time appeared		Linux Linux linux Kernel
CPEs		cpe:2.3:o:linux:linux_kernel::::::::
Vendors & Products		Linux Linux linux Kernel
References		https://git.kernel.org/stable/c/06600719d0f7a723811c45e4d51f5b742f345309 https://git.kernel.org/stable/c/2857bd59feb63fcf40fe4baf55401baea6b4feb4 https://git.kernel.org/stable/c/34eb22836e0cdba093baac66599d68c4cd245a9d https://git.kernel.org/stable/c/53f07d095e7e680c5e4569a55a019f2c0348cdc6 https://git.kernel.org/stable/c/ba4811c8b433bfa681729ca42cc62b6034f223b0 https://git.kernel.org/stable/c/ca97360860eb02e3ae4ba42c19b439a0fcecbf06 https://git.kernel.org/stable/c/e8bfa2401d4c51eca6e48e9b33c798828ca9df61

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-22980", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-01-13T15:37:45.936Z", "datePublished": "2026-01-23T15:24:02.924Z", "dateUpdated": "2026-01-23T15:24:02.924Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-01-23T15:24:02.924Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: provide locking for v4_end_grace\n\nWriting to v4_end_grace can race with server shutdown and result in\nmemory being accessed after it was freed - reclaim_str_hashtbl in\nparticularly.\n\nWe cannot hold nfsd_mutex across the nfsd4_end_grace() call as that is\nheld while client_tracking_op->init() is called and that can wait for\nan upcall to nfsdcltrack which can write to v4_end_grace, resulting in a\ndeadlock.\n\nnfsd4_end_grace() is also called by the landromat work queue and this\ndoesn't require locking as server shutdown will stop the work and wait\nfor it before freeing anything that nfsd4_end_grace() might access.\n\nHowever, we must be sure that writing to v4_end_grace doesn't restart\nthe work item after shutdown has already waited for it. For this we\nadd a new flag protected with nn->client_lock. It is set only while it\nis safe to make client tracking calls, and v4_end_grace only schedules\nwork while the flag is set with the spinlock held.\n\nSo this patch adds a nfsd_net field \"client_tracking_active\" which is\nset as described. Another field \"grace_end_forced\", is set when\nv4_end_grace is written. After this is set, and providing\nclient_tracking_active is set, the laundromat is scheduled.\nThis \"grace_end_forced\" field bypasses other checks for whether the\ngrace period has finished.\n\nThis resolves a race which can result in use-after-free."}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/nfsd/netns.h", "fs/nfsd/nfs4state.c", "fs/nfsd/nfsctl.c", "fs/nfsd/state.h"], "versions": [{"version": "7f5ef2e900d9462bf9cffaf6bb246ed87a20a6d6", "lessThan": "ca97360860eb02e3ae4ba42c19b439a0fcecbf06", "status": "affected", "versionType": "git"}, {"version": "7f5ef2e900d9462bf9cffaf6bb246ed87a20a6d6", "lessThan": "e8bfa2401d4c51eca6e48e9b33c798828ca9df61", "status": "affected", "versionType": "git"}, {"version": "7f5ef2e900d9462bf9cffaf6bb246ed87a20a6d6", "lessThan": "34eb22836e0cdba093baac66599d68c4cd245a9d", "status": "affected", "versionType": "git"}, {"version": "7f5ef2e900d9462bf9cffaf6bb246ed87a20a6d6", "lessThan": "06600719d0f7a723811c45e4d51f5b742f345309", "status": "affected", "versionType": "git"}, {"version": "7f5ef2e900d9462bf9cffaf6bb246ed87a20a6d6", "lessThan": "ba4811c8b433bfa681729ca42cc62b6034f223b0", "status": "affected", "versionType": "git"}, {"version": "7f5ef2e900d9462bf9cffaf6bb246ed87a20a6d6", "lessThan": "53f07d095e7e680c5e4569a55a019f2c0348cdc6", "status": "affected", "versionType": "git"}, {"version": "7f5ef2e900d9462bf9cffaf6bb246ed87a20a6d6", "lessThan": "2857bd59feb63fcf40fe4baf55401baea6b4feb4", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/nfsd/netns.h", "fs/nfsd/nfs4state.c", "fs/nfsd/nfsctl.c", "fs/nfsd/state.h"], "versions": [{"version": "3.18", "status": "affected"}, {"version": "0", "lessThan": "3.18", "status": "unaffected", "versionType": "semver"}, {"version": "5.10.248", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver"}, {"version": "5.15.198", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.1.161", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.121", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.66", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.6", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.19-rc5", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.18", "versionEndExcluding": "5.10.248"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.18", "versionEndExcluding": "5.15.198"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.18", "versionEndExcluding": "6.1.161"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.18", "versionEndExcluding": "6.6.121"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.18", "versionEndExcluding": "6.12.66"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.18", "versionEndExcluding": "6.18.6"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.18", "versionEndExcluding": "6.19-rc5"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/ca97360860eb02e3ae4ba42c19b439a0fcecbf06"}, {"url": "https://git.kernel.org/stable/c/e8bfa2401d4c51eca6e48e9b33c798828ca9df61"}, {"url": "https://git.kernel.org/stable/c/34eb22836e0cdba093baac66599d68c4cd245a9d"}, {"url": "https://git.kernel.org/stable/c/06600719d0f7a723811c45e4d51f5b742f345309"}, {"url": "https://git.kernel.org/stable/c/ba4811c8b433bfa681729ca42cc62b6034f223b0"}, {"url": "https://git.kernel.org/stable/c/53f07d095e7e680c5e4569a55a019f2c0348cdc6"}, {"url": "https://git.kernel.org/stable/c/2857bd59feb63fcf40fe4baf55401baea6b4feb4"}], "title": "nfsd: provide locking for v4_end_grace", "x_generator": {"engine": "bippy-1.2.0"}}}}

{"cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: provide locking for v4_end_grace\n\nWriting to v4_end_grace can race with server shutdown and result in\nmemory being accessed after it was freed - reclaim_str_hashtbl in\nparticularly.\n\nWe cannot hold nfsd_mutex across the nfsd4_end_grace() call as that is\nheld while client_tracking_op->init() is called and that can wait for\nan upcall to nfsdcltrack which can write to v4_end_grace, resulting in a\ndeadlock.\n\nnfsd4_end_grace() is also called by the landromat work queue and this\ndoesn't require locking as server shutdown will stop the work and wait\nfor it before freeing anything that nfsd4_end_grace() might access.\n\nHowever, we must be sure that writing to v4_end_grace doesn't restart\nthe work item after shutdown has already waited for it. For this we\nadd a new flag protected with nn->client_lock. It is set only while it\nis safe to make client tracking calls, and v4_end_grace only schedules\nwork while the flag is set with the spinlock held.\n\nSo this patch adds a nfsd_net field \"client_tracking_active\" which is\nset as described. Another field \"grace_end_forced\", is set when\nv4_end_grace is written. After this is set, and providing\nclient_tracking_active is set, the laundromat is scheduled.\nThis \"grace_end_forced\" field bypasses other checks for whether the\ngrace period has finished.\n\nThis resolves a race which can result in use-after-free."}], "id": "CVE-2026-22980", "lastModified": "2026-01-23T16:15:54.003", "metrics": {}, "published": "2026-01-23T16:15:54.003", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/06600719d0f7a723811c45e4d51f5b742f345309"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/2857bd59feb63fcf40fe4baf55401baea6b4feb4"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/34eb22836e0cdba093baac66599d68c4cd245a9d"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/53f07d095e7e680c5e4569a55a019f2c0348cdc6"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/ba4811c8b433bfa681729ca42cc62b6034f223b0"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/ca97360860eb02e3ae4ba42c19b439a0fcecbf06"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/e8bfa2401d4c51eca6e48e9b33c798828ca9df61"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

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