138 lines
7.6 KiB
JSON
138 lines
7.6 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-2026-93147",
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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": "2026-09-17T16:02:15.088Z",
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"datePublished": "2026-09-17T16:11:44.793Z",
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"dateUpdated": "2026-10-19T09:06:19.689Z"
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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": "2026-10-19T09:06:19.689Z"
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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\ns390/bpf: Replace ly instruction with llgf\n\ncpu_nr is a 32 bit value and BPF_REG_0 is a 64 bit register, when ly loads\nthe cpu_nr into BPF_REG_0 it does not zero the upper bits, but llgf does."
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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 malformed input is eBPF bytecode containing BPF_JMP|BPF_CALL with imm=BPF_FUNC_get_smp_processor_id, loaded via bpf_prog_load() (bpf(2) BPF_PROG_LOAD). s390 bpf_jit_insn() then inlines that call as LY from get_lowcore()->cpu_nr; no remote protocol carries this bytecode.\nAC:L - The attacker sets BPF_REG_0 (s390 %r14) with BPF_LD_IMM64, then emits the helper call; bpf_jit_insn() always compiles it to LY (E358), which writes only bits 32-63 and leaves the attacker-chosen high half intact. bpf_opt_remove_dead_code() does not delete that store, and there is no race.\nPR:L - bpf_prog_load() allows BPF_PROG_TYPE_SOCKET_FILTER; sk_filter_func_proto() reaches bpf_base_func_proto(), which returns bpf_get_raw_smp_processor_id_proto for BPF_FUNC_get_smp_processor_id before its CAP_BPF gate, and BPF_MAP_TYPE_ARRAY is an unprivileged map. CAP_BPF is also granted by bpf_token_capable() in a delegated user namespace.\nUI:N - The attacker loads the crafted program with bpf(BPF_PROG_LOAD) and executes it themselves via BPF_PROG_TEST_RUN (sk_filter_prog_ops.test_run = bpf_prog_test_run_skb) or SO_ATTACH_BPF on their own socket; no other user must mount, open, or otherwise act.\nS:U - LY leaving stale high bits in BPF_REG_0 lets the JITed program read and write the host kernel through a verifier-approved PTR_TO_MAP_VALUE. That stays inside the same kernel authority; it is not a KVM guest-to-host or IOMMU bypass.\nC:H - do_refine_retval_range() sets R0’s 64-bit range to [0, nr_cpu_ids-1] after BPF_FUNC_get_smp_processor_id, so check_map_access() allows adding it to a map-value pointer. LY preserves attacker high bits, so the subsequent BPF_LDX reads kernel memory far outside the map.\nI:H - The same forged pointer is a BPF_STX destination: the store lands at map_value + ((old_r0 & 0xFFFFFFFF00000000) | cpu_nr). That is an attacker-controlled kernel write usable for corruption and control-flow hijack.\nA:H - Using that out-of-bounds map-value pointer (map_value plus the uncleared high 32 bits of %r14 after LY of cpu_nr) faults on unmapped addresses and oopses or panics 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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"arch/s390/net/bpf_jit_comp.c"
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],
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"versions": [
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{
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"version": "9012cf2491e3c5d28d098b0d6da804af82977032",
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"lessThan": "88500a86ab79f01c568de6ed00f5b1c5c79f11d5",
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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": "9012cf2491e3c5d28d098b0d6da804af82977032",
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"lessThan": "5f6cc299938b561cb01e343bab7042611fcee12a",
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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/s390/net/bpf_jit_comp.c"
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],
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"versions": [
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{
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"version": "7.2",
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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": "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": "7.2.6",
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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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"versionStartIncluding": "7.2",
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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": "7.2",
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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/88500a86ab79f01c568de6ed00f5b1c5c79f11d5"
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},
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{
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"url": "https://git.kernel.org/stable/c/5f6cc299938b561cb01e343bab7042611fcee12a"
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}
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],
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"title": "s390/bpf: Replace ly instruction with llgf",
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