256 lines
14 KiB
JSON
256 lines
14 KiB
JSON
{
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"dataType": "CVE_RECORD",
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"dataVersion": "5.2",
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"cveMetadata": {
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"cveId": "CVE-2026-89686",
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"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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"state": "PUBLISHED",
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"assignerShortName": "Linux",
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"dateReserved": "2026-09-11T19:38:34.749Z",
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"datePublished": "2026-09-11T19:46:07.877Z",
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"dateUpdated": "2026-10-30T12:32:43.218Z"
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},
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"containers": {
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"cna": {
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"providerMetadata": {
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"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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"shortName": "Linux",
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"dateUpdated": "2026-10-30T12:32:43.218Z"
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},
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"descriptions": [
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{
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"lang": "en",
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: fix BUG_ON in nfsd4_alloc_layout_stateid on racing delegation revoke\n\nnfsd4_alloc_layout_stateid reads fp->fi_deleg_file without holding\nfi_lock when the parent stateid is a delegation. A concurrent delegation\nrevoke via the laundromat can clear fi_deleg_file under fi_lock, causing\nnfsd_file_get() to return NULL and triggering the BUG_ON.\n\nThis race is client-reachable: two NFS clients can trigger it by having\none hold a delegation while another opens the same file to force a\nrecall. When the first client doesn't respond to the recall, the\nlaundromat revokes it. A concurrent LAYOUTGET from any client using the\ndelegation stateid hits the race window.\n\nFix this by taking fi_lock around the fi_deleg_file read in the\nSC_TYPE_DELEG path, matching the locking discipline of the\nfind_any_file() arm, and replacing the BUG_ON with a graceful error\nreturn that cleans up the partially-initialized layout stateid."
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}
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],
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"metrics": [
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{
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"cvssV3_1": {
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"version": "3.1",
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"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
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"baseScore": 9.8,
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"baseSeverity": "CRITICAL"
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},
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"scenarios": [
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{
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"lang": "en",
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"value": "AV:N - The flaw is in nfsd pNFS LAYOUTGET (nfsd4_alloc_layout_stateid in fs/nfsd/nfs4layouts.c). A remote NFSv4.1 client reaches it over TCP/2049 via nfsd_dispatch to nfsd4_proc_compound to nfsd4_layoutget, so no local access to the NFS server is required.\nAC:L - The attacker controls both sides of the race: one NFS client obtains a delegation while another OPENs the same file to force recall, then the first client withholds CB_RECALL and issues concurrent LAYOUTGET with the delegation stateid as the laundromat runs put_deleg_file. The sequence is retryable and can be timed using FATTR4_LEASE_TIME.\nPR:N - Typical nfsd deployments accept AUTH_SYS/AUTH_NULL without cryptographic authentication. Any host allowed by the export ACL can EXCHANGE_ID/CREATE_SESSION, OPEN to receive a delegation, and LAYOUTGET; no local account or capability on the NFS server is required.\nUI:N - The attacking NFS clients drive the OPEN, recall, and LAYOUTGET compounds themselves against an already-running nfsd export. No victim user action such as mounting a filesystem or opening a file on the server is required.\nS:U - The unlocked fi_deleg_file load and resulting BUG_ON or nfsd_file use-after-free occur in kernel nfsd state on the NFS server host. Impact stays in that kernel security authority and does not cross a VM, IOMMU, or sandbox boundary.\nC:H - put_deleg_file may drop the last nfsd_file ref and call_rcu-free it (KMEM_CACHE flags 0, not SLAB_TYPESAFE_BY_RCU) while LAYOUTGET still calls nfsd_file_get on the stale pointer. After slab reuse the layout stateid's nf_file can be leveraged for kernel information disclosure.\nI:H - The same stale nfsd_file pointer is used for refcount_inc_not_zero and later nfsd4_layout_setlease/kernel_setlease on nf_file. Heap reuse of the nfsd_file slab enables an arbitrary write or control-flow hijack per kernel UAF scoring guidance.\nA:H - When nfsd_file_get returns NULL the original code hits BUG_ON(!ls->ls_file), oopsing or panicking the nfsd thread. Even without that assertion, use-after-free of nfsd_file crashes nfsd, and the attacker can repeat LAYOUTGET to deny NFS service."
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}
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]
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}
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],
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"affected": [
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{
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"product": "Linux",
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"vendor": "Linux",
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"defaultStatus": "unaffected",
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"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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"programFiles": [
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"fs/nfsd/nfs4layouts.c"
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],
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"versions": [
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{
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"version": "c5c707f96fc9a6e5a57ca5baac892673270abe3d",
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"lessThan": "f5011c26246d1abed3dc750c9744e33cb79ff9bc",
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"status": "affected",
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"versionType": "git"
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},
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{
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"version": "c5c707f96fc9a6e5a57ca5baac892673270abe3d",
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"lessThan": "d12af460df27876661707efab3a8532146cb961f",
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"status": "affected",
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"versionType": "git"
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},
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{
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"version": "c5c707f96fc9a6e5a57ca5baac892673270abe3d",
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"lessThan": "c517f27498757e616d2a8fe6d16caad1fee422e6",
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"status": "affected",
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"versionType": "git"
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},
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{
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"version": "c5c707f96fc9a6e5a57ca5baac892673270abe3d",
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"lessThan": "607a56fea772c1f4f4989d8e255dd4f7192d9604",
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"status": "affected",
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"versionType": "git"
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},
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{
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"version": "c5c707f96fc9a6e5a57ca5baac892673270abe3d",
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"lessThan": "97bda8b4284d90897a1f1922e5082ff9e35d7c7e",
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"status": "affected",
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"versionType": "git"
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},
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{
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"version": "c5c707f96fc9a6e5a57ca5baac892673270abe3d",
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"lessThan": "ca94ba36172046be6a694a7986f6931e47ed4d51",
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"status": "affected",
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"versionType": "git"
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}
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]
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},
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{
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"product": "Linux",
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"vendor": "Linux",
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"defaultStatus": "affected",
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"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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"programFiles": [
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"fs/nfsd/nfs4layouts.c"
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],
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"versions": [
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{
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"version": "4.0",
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"status": "affected"
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},
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{
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"version": "0",
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"lessThan": "4.0",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "6.1.191",
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"lessThanOrEqual": "6.1.*",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "6.6.160",
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"lessThanOrEqual": "6.6.*",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "6.12.109",
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"lessThanOrEqual": "6.12.*",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "6.18.50",
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"lessThanOrEqual": "6.18.*",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "7.2.4",
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"lessThanOrEqual": "7.2.*",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "7.3",
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"lessThanOrEqual": "*",
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"status": "unaffected",
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"versionType": "original_commit_for_fix"
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}
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]
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}
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],
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"cpeApplicability": [
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{
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"nodes": [
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{
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"operator": "OR",
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"negate": false,
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"cpeMatch": [
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{
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"vulnerable": true,
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionStartIncluding": "4.0",
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"versionEndExcluding": "6.1.191"
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},
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{
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"vulnerable": true,
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionStartIncluding": "4.0",
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"versionEndExcluding": "6.6.160"
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},
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{
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"vulnerable": true,
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionStartIncluding": "4.0",
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"versionEndExcluding": "6.12.109"
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{
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"vulnerable": true,
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionStartIncluding": "4.0",
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"versionEndExcluding": "6.18.50"
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{
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"vulnerable": true,
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionStartIncluding": "4.0",
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"versionEndExcluding": "7.2.4"
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},
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{
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"vulnerable": true,
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionStartIncluding": "4.0",
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"versionEndExcluding": "7.3"
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}
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]
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}
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]
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}
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],
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"references": [
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{
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"url": "https://git.kernel.org/stable/c/f5011c26246d1abed3dc750c9744e33cb79ff9bc"
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},
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{
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"url": "https://git.kernel.org/stable/c/d12af460df27876661707efab3a8532146cb961f"
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},
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{
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"url": "https://git.kernel.org/stable/c/c517f27498757e616d2a8fe6d16caad1fee422e6"
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},
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{
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"url": "https://git.kernel.org/stable/c/607a56fea772c1f4f4989d8e255dd4f7192d9604"
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},
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{
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"url": "https://git.kernel.org/stable/c/97bda8b4284d90897a1f1922e5082ff9e35d7c7e"
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},
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{
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"url": "https://git.kernel.org/stable/c/ca94ba36172046be6a694a7986f6931e47ed4d51"
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}
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],
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"title": "nfsd: fix BUG_ON in nfsd4_alloc_layout_stateid on racing delegation revoke",
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"x_generator": {
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"engine": "bippy-1.2.0"
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}
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},
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"adp": [
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{
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"metrics": [
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{
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"other": {
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"type": "ssvc",
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"content": {
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"id": "CVE-2026-89686",
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"role": "CISA Coordinator",
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"options": [
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{
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"Exploitation": "none"
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},
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{
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"Automatable": "yes"
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},
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{
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"Technical Impact": "total"
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}
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],
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"version": "2.0.3",
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"timestamp": "2026-10-16T19:26:03.140311Z"
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}
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}
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}
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],
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"title": "CISA ADP Vulnrichment",
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"providerMetadata": {
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"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
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"shortName": "CISA-ADP",
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"dateUpdated": "2026-10-16T19:26:48.827Z"
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}
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}
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]
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}
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} |