172 lines
12 KiB
JSON
172 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-2022-49760",
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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": "2025-03-27T16:39:17.990Z",
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"datePublished": "2025-03-27T16:43:07.001Z",
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"dateUpdated": "2026-10-15T21:21:08.123Z"
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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": "2026-08-05T08:56:14.458Z"
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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\nmm/hugetlb: fix PTE marker handling in hugetlb_change_protection()\n\nPatch series \"mm/hugetlb: uffd-wp fixes for hugetlb_change_protection()\".\n\nPlaying with virtio-mem and background snapshots (using uffd-wp) on\nhugetlb in QEMU, I managed to trigger a VM_BUG_ON(). Looking into the\ndetails, hugetlb_change_protection() seems to not handle uffd-wp correctly\nin all cases.\n\nPatch #1 fixes my test case. I don't have reproducers for patch #2, as it\nrequires running into migration entries.\n\nI did not yet check in detail yet if !hugetlb code requires similar care.\n\n\nThis patch (of 2):\n\nThere are two problematic cases when stumbling over a PTE marker in\nhugetlb_change_protection():\n\n(1) We protect an uffd-wp PTE marker a second time using uffd-wp: we will\n end up in the \"!huge_pte_none(pte)\" case and mess up the PTE marker.\n\n(2) We unprotect a uffd-wp PTE marker: we will similarly end up in the\n \"!huge_pte_none(pte)\" case even though we cleared the PTE, because\n the \"pte\" variable is stale. We'll mess up the PTE marker.\n\nFor example, if we later stumble over such a \"wrongly modified\" PTE marker,\nwe'll treat it like a present PTE that maps some garbage page.\n\nThis can, for example, be triggered by mapping a memfd backed by huge\npages, registering uffd-wp, uffd-wp'ing an unmapped page and (a)\nuffd-wp'ing it a second time; or (b) uffd-unprotecting it; or (c)\nunregistering uffd-wp. Then, ff we trigger fallocate(FALLOC_FL_PUNCH_HOLE)\non that file range, we will run into a VM_BUG_ON:\n\n[ 195.039560] page:00000000ba1f2987 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x0\n[ 195.039565] flags: 0x7ffffc0001000(reserved|node=0|zone=0|lastcpupid=0x1fffff)\n[ 195.039568] raw: 0007ffffc0001000 ffffe742c0000008 ffffe742c0000008 0000000000000000\n[ 195.039569] raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000\n[ 195.039569] page dumped because: VM_BUG_ON_PAGE(compound && !PageHead(page))\n[ 195.039573] ------------[ cut here ]------------\n[ 195.039574] kernel BUG at mm/rmap.c:1346!\n[ 195.039579] invalid opcode: 0000 [#1] PREEMPT SMP NOPTI\n[ 195.039581] CPU: 7 PID: 4777 Comm: qemu-system-x86 Not tainted 6.0.12-200.fc36.x86_64 #1\n[ 195.039583] Hardware name: LENOVO 20WNS1F81N/20WNS1F81N, BIOS N35ET50W (1.50 ) 09/15/2022\n[ 195.039584] RIP: 0010:page_remove_rmap+0x45b/0x550\n[ 195.039588] Code: [...]\n[ 195.039589] RSP: 0018:ffffbc03c3633ba8 EFLAGS: 00010292\n[ 195.039591] RAX: 0000000000000040 RBX: ffffe742c0000000 RCX: 0000000000000000\n[ 195.039592] RDX: 0000000000000002 RSI: ffffffff8e7aac1a RDI: 00000000ffffffff\n[ 195.039592] RBP: 0000000000000001 R08: 0000000000000000 R09: ffffbc03c3633a08\n[ 195.039593] R10: 0000000000000003 R11: ffffffff8f146328 R12: ffff9b04c42754b0\n[ 195.039594] R13: ffffffff8fcc6328 R14: ffffbc03c3633c80 R15: ffff9b0484ab9100\n[ 195.039595] FS: 00007fc7aaf68640(0000) GS:ffff9b0bbf7c0000(0000) knlGS:0000000000000000\n[ 195.039596] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n[ 195.039597] CR2: 000055d402c49110 CR3: 0000000159392003 CR4: 0000000000772ee0\n[ 195.039598] PKRU: 55555554\n[ 195.039599] Call Trace:\n[ 195.039600] <TASK>\n[ 195.039602] __unmap_hugepage_range+0x33b/0x7d0\n[ 195.039605] unmap_hugepage_range+0x55/0x70\n[ 195.039608] hugetlb_vmdelete_list+0x77/0xa0\n[ 195.039611] hugetlbfs_fallocate+0x410/0x550\n[ 195.039612] ? _raw_spin_unlock_irqrestore+0x23/0x40\n[ 195.039616] vfs_fallocate+0x12e/0x360\n[ 195.039618] __x64_sys_fallocate+0x40/0x70\n[ 195.039620] do_syscall_64+0x58/0x80\n[ 195.039623] ? syscall_exit_to_user_mode+0x17/0x40\n[ 195.039624] ? do_syscall_64+0x67/0x80\n[ 195.039626] entry_SYSCALL_64_after_hwframe+0x63/0xcd\n[ 195.039628] RIP: 0033:0x7fc7b590651f\n[ 195.039653] Code: [...]\n[ 195.039654] RSP: 002b:00007fc7aaf66e70 EFLAGS: 00000293 ORIG_RAX: 000000000000011d\n[ 195.039655] RAX: ffffffffffffffda RBX: 0000558ef4b7f370 RCX: 00007fc7b590651f\n---truncated---"
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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:U/C:H/I:H/A:H",
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"baseScore": 7.8,
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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 - Reachable only via local syscalls: memfd_create(MFD_HUGETLB)/mmap, userfaultfd + UFFDIO_WRITEPROTECT/unregister (into hugetlb_change_protection), then fallocate(PUNCH_HOLE). Not network-facing.\nAC:L - The commit documents a deterministic trigger (double uffd-wp, unprotect, or unregister on an unmapped hugetlb PTE marker); the attacker fully controls the sequence with no race or external condition.\nPR:L - An unprivileged user can open userfaultfd with UFFD_USER_MODE_ONLY (always allowed) and create hugetlb memfds via HUGETLB_ANONHUGE_INODE without CAP_IPC_LOCK; no real root is required.\nUI:N - The attacker performs all setup and the triggering fallocate on their own mappings; no victim action is needed.\nS:U - Impact is confined to the local kernel/process authority (page-table corruption and crash); this is not a VM/IOMMU/sandbox boundary escape.\nC:H - Corrupted uffd-wp markers are rewritten as present PTEs mapping a garbage PFN, so later walks/unmaps operate on the wrong page and can disclose kernel/physical memory contents.\nI:H - Without CONFIG_DEBUG_VM the VM_BUG_ON is a no-op, so page_remove_rmap/tlb_remove_page_size proceed on the wrong page, corrupting mapcounts and potentially freeing unrelated pages—full integrity compromise.\nA:H - The documented path hits VM_BUG_ON/kernel BUG in page_remove_rmap, and the production non-debug path still risks oops/panic from corrupt page-table and rmap state."
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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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"mm/hugetlb.c"
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],
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"versions": [
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{
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"version": "60dfaad65aa97fb6755b9798a6b3c9e79bcd5930",
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"lessThan": "6062c992e912df1eedad52cf64efb3d48e8d35c5",
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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": "60dfaad65aa97fb6755b9798a6b3c9e79bcd5930",
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"lessThan": "0e678153f5be7e6c8d28835f5a678618da4b7a9c",
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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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"mm/hugetlb.c"
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],
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"versions": [
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{
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"version": "5.19",
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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": "5.19",
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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": "6.1.8",
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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": "6.2",
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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": "5.19",
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"versionEndExcluding": "6.1.8"
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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": "5.19",
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"versionEndExcluding": "6.2"
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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/6062c992e912df1eedad52cf64efb3d48e8d35c5"
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},
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{
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"url": "https://git.kernel.org/stable/c/0e678153f5be7e6c8d28835f5a678618da4b7a9c"
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}
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],
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"title": "mm/hugetlb: fix PTE marker handling in hugetlb_change_protection()",
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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-2022-49760",
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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": "no"
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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": "2026-10-15T21:18:16.874914Z"
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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": "2026-10-15T21:21:08.123Z"
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}
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}
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]
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}
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} |