180 lines
10 KiB
JSON
180 lines
10 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-2026-93045",
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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": "2026-09-17T15:57:05.658Z",
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"datePublished": "2026-09-17T16:10:36.988Z",
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"dateUpdated": "2026-10-19T09:04:40.316Z"
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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": "2026-10-19T09:04:40.316Z"
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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\nbpf: Reject arena frees below the arena base\n\nbpf_arena_free_pages() accepts scalar arena addresses. The runtime\nmasks the address to the low 32 bits and reconstructs a full user\naddress from the arena base before returning the range to the arena\nfree tree.\n\nWhen the scalar value is below the low 32 bits of the arena base,\nfull_uaddr falls below user_vm_start. The existing upper-end clipping\nthen turns this into an out-of-range free-tree offset. A later\nallocation can reuse that offset and return an address below the arena\nmapping.\n\nReject such frees before computing the clipped range."
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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 - The attacker-controlled input is the scalar ptr passed to bpf_arena_free_pages() from a locally loaded BPF program after bpf(BPF_MAP_CREATE) of BPF_MAP_TYPE_ARENA, mmap() of that map, bpf(BPF_PROG_LOAD), and bpf(BPF_PROG_TEST_RUN) (e.g. BPF_PROG_TYPE_SYSCALL). The below-base address is not carried in a network protocol message.\nAC:L - The attacker chooses the scalar whose low 32 bits are below (u32)arena->user_vm_start and the page_cnt passed to bpf_arena_free_pages(); compute_pgoff() then underflows and range_tree_set() records that offset deterministically. No race, victim state, or rare non-default config is required on JITs that implement bpf_jit_supports_arena() (x86_64/arm64).\nPR:L - map_create() requires bpf_token_capable(CAP_BPF) for BPF_MAP_TYPE_ARENA, and check_map_prog_compatibility() additionally requires CAP_PERFMON (env->allow_ptr_leaks) before a program may reference the arena. Those caps are delegable through BPF tokens into a user namespace rather than requiring init-namespace root.\nUI:N - The attacker creates their own arena map, mmap()s it so user_vm_start is set, loads their own program that calls bpf_arena_free_pages() with a below-base scalar, and runs it via BPF_PROG_TEST_RUN. No separate victim mount, open, or other interaction is required.\nS:U - arena_free_pages() corrupts the arena range_tree and kernel PTEs of the same host kernel that loaded the program. This is in-kernel memory unsafety, not a KVM/Xen guest-to-host escape or IOMMU/DMA boundary cross.\nC:H - With a below-base scalar and a large page_cnt, arena_free_pages() clips uaddr_end to user_vm_end so apply_to_existing_page_range() walks from kern_vm_start+uaddr32 across in-use arena PTEs and __free_page()s those pages while compute_pgoff() records a wrapped offset, leaving a page UAF that can disclose kernel memory.\nI:H - The same clipped free desynchronizes PTEs from the range_tree, and zap_pages() calls zap_vma_range() with full_uaddr below vma->vm_start, clearing mm PTEs outside the arena VMA. A later bpf_arena_alloc_pages() reuses the out-of-range offset via range_tree_find(), giving an exploitable page-reuse write primitive.\nA:H - Accessing a below-base pointer with a negative LDX/STX off faults below kern_vm_start, where bpf_arena_handle_page_fault() refuses recovery and oopses; zap_vma_range() also VM_WARN_ON_ONCE()s for a range outside the arena VMA, and the UAF of freed arena pages can panic the kernel."
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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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"kernel/bpf/arena.c"
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],
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"versions": [
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{
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"version": "317460317a02a1af512697e6e964298dedd8a163",
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"lessThan": "90453eaf8f14e7be0ab03983f2a93aeb6b990a58",
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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": "317460317a02a1af512697e6e964298dedd8a163",
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"lessThan": "a968dffa5ab3c74d2ebb3a6233bf8b843f0bfc20",
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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": "317460317a02a1af512697e6e964298dedd8a163",
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"lessThan": "8a08635656037aee9c12231ed384449c4ffb1a93",
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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": "317460317a02a1af512697e6e964298dedd8a163",
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"lessThan": "b5a71cb2db6d84ac0042549dcec266b18429d41e",
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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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"kernel/bpf/arena.c"
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],
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"versions": [
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{
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"version": "6.9",
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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": "6.9",
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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": "6.12.110",
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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": "6.18.52",
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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": "7.2.6",
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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": "6.9",
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"versionEndExcluding": "6.12.110"
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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": "6.9",
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"versionEndExcluding": "6.18.52"
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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": "6.9",
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"versionEndExcluding": "7.2.6"
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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": "6.9",
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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/90453eaf8f14e7be0ab03983f2a93aeb6b990a58"
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},
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{
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"url": "https://git.kernel.org/stable/c/a968dffa5ab3c74d2ebb3a6233bf8b843f0bfc20"
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},
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{
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"url": "https://git.kernel.org/stable/c/8a08635656037aee9c12231ed384449c4ffb1a93"
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},
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{
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"url": "https://git.kernel.org/stable/c/b5a71cb2db6d84ac0042549dcec266b18429d41e"
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}
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],
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"title": "bpf: Reject arena frees below the arena base",
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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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} |