222 lines
12 KiB
JSON
222 lines
12 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-2026-98283",
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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": "2026-09-25T10:25:14.335Z",
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"datePublished": "2026-10-06T08:45:44.593Z",
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"dateUpdated": "2026-10-19T09:16:54.747Z"
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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": "2026-10-19T09:16:54.747Z"
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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\nKVM: PPC: Book3S HV: fix use-after-free in kvmhv_emulate_tlbie_all_lpid()\n\nkvmhv_emulate_tlbie_all_lpid() iterates the nested-guest IDR and drops\nmmu_lock before calling kvmhv_emulate_tlbie_lpid(), but does not hold a\nreference on the kvm_nested_guest pointer obtained from the IDR. A\nconcurrent vCPU issuing a single-LPID tlbie (is=2, ric=2) can race\nthrough kvmhv_flush_nested() -> kvmhv_remove_nested() -> idr_remove /\n--refcnt -> kvmhv_release_nested() -> kfree(gp) in that window, leaving\nthe iterating vCPU with a dangling pointer. The subsequent\nmutex_lock(&gp->tlb_lock) and accesses to gp->shadow_pgtable,\ngp->shadow_lpid and gp->l1_host all touch freed memory. The free path\nis fully L1-controlled.\n\nFix this by incrementing gp->refcnt inside the loop before dropping\nmmu_lock, mirroring what kvmhv_get_nested() does, and releasing the\nreference with kvmhv_put_nested() after the per-guest work completes.\nThis is the same get/put discipline already used at every other\ncall site that drops mmu_lock while holding a nested-guest pointer."
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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:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
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"baseScore": 8.8,
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"baseSeverity": "HIGH"
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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:L - The trigger is the H_TLB_INVALIDATE hcall made by code running inside an L1 guest on the POWER KVM-HV host, via kvmppc_pseries_do_hcall -> kvmhv_do_nested_tlbie -> kvmhv_emulate_priv_tlbie -> kvmhv_emulate_tlbie_all_lpid. No network protocol carries the input; the attacker needs code execution in a local guest.\nAC:L - The L1 controls both sides of the race: one vCPU issues tlbie is=3 (all-LPID walk), another issues is=2 ric=2 after zeroing its own partition-table entry so kvmhv_flush_nested() calls kvmhv_remove_nested() and kfree(gp). Contention on gp->tlb_lock widens the window and the attempt can be repeated. The only outside requirement is the VMM enabling KVM_CAP_PPC_NESTED_HV.\nPR:L - The attacker needs kernel/hypervisor-mode code in a nested-enabled L1 guest, which an ordinary tenant owns, but holds no privilege on the L0 host. The nesting_enabled() check is the only gate before kvmhv_do_nested_tlbie().\nUI:N - The L1 guest issues every hcall and controls every partition-table entry involved. No host operator or other user has to do anything.\nS:C - A guest-controlled vulnerability corrupts memory in the L0 host kernel (the kfree'd kvm_nested_guest object), which crosses the guest-to-host boundary.\nC:H - After the free, kvmhv_emulate_tlbie_lpid() reads gp->shadow_pgtable, gp->shadow_lpid and gp->l1_host from the dangling object. A reclaimed object lets the guest steer host page-table walks and host data reads.\nI:H - The freed gp is used for mutex_lock(&gp->tlb_lock), kvmppc_free_pgtable_radix() on gp->shadow_pgtable, and kvmhv_flush_nested()/kvmhv_put_nested() refcount writes. With a reclaimed object, these become host-kernel write and free primitives the guest controls.\nA:H - Using the freed kvm_nested_guest in the host can oops or panic the L0 host kernel, taking down every guest on the machine. The L1 can trigger it again at will."
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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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"arch/powerpc/kvm/book3s_hv_nested.c"
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],
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"versions": [
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{
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"version": "e3b6b4661527e821ffbe3db83952fdb1e6e47c49",
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"lessThan": "4d8f7b1f586375df8bce23a0909566ad5e852259",
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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": "e3b6b4661527e821ffbe3db83952fdb1e6e47c49",
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"lessThan": "e37fba1ba69385cff2d0e60b371ee19e7d1852d1",
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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": "e3b6b4661527e821ffbe3db83952fdb1e6e47c49",
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"lessThan": "24b634852413229bb8340d908b115c3365f3a247",
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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": "e3b6b4661527e821ffbe3db83952fdb1e6e47c49",
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"lessThan": "fbf69b7d0555ee83c871f58750770f74b7179ad1",
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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": "e3b6b4661527e821ffbe3db83952fdb1e6e47c49",
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"lessThan": "ec2d7a52b3996ae81131617b4afc0af31583c1b4",
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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": "e3b6b4661527e821ffbe3db83952fdb1e6e47c49",
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"lessThan": "51938dfa8a51a4f85328413fca9b6e21f9d2d088",
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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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"arch/powerpc/kvm/book3s_hv_nested.c"
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],
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"versions": [
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{
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"version": "4.20",
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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": "4.20",
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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": "6.1.189",
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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": "6.6.158",
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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": "6.12.112",
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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": "6.18.54",
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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": "7.2.8",
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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": "4.20",
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"versionEndExcluding": "6.1.189"
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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": "4.20",
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"versionEndExcluding": "6.6.158"
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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": "4.20",
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"versionEndExcluding": "6.12.112"
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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": "4.20",
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"versionEndExcluding": "6.18.54"
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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": "4.20",
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"versionEndExcluding": "7.2.8"
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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": "4.20",
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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/4d8f7b1f586375df8bce23a0909566ad5e852259"
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},
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{
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"url": "https://git.kernel.org/stable/c/e37fba1ba69385cff2d0e60b371ee19e7d1852d1"
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},
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{
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"url": "https://git.kernel.org/stable/c/24b634852413229bb8340d908b115c3365f3a247"
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},
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{
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"url": "https://git.kernel.org/stable/c/fbf69b7d0555ee83c871f58750770f74b7179ad1"
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},
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{
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"url": "https://git.kernel.org/stable/c/ec2d7a52b3996ae81131617b4afc0af31583c1b4"
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},
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{
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"url": "https://git.kernel.org/stable/c/51938dfa8a51a4f85328413fca9b6e21f9d2d088"
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}
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],
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"title": "KVM: PPC: Book3S HV: fix use-after-free in kvmhv_emulate_tlbie_all_lpid()",
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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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}
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} |