159 lines
10 KiB
JSON
159 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-2026-90312",
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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": "2026-09-11T19:38:34.801Z",
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"datePublished": "2026-09-17T16:08:32.287Z",
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"dateUpdated": "2026-10-19T09:01:28.834Z"
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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": "2026-10-19T09:01:28.834Z"
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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: Check load-acquire src ptr type before the load\n\ncheck_atomic_load() calls check_load_mem() before atomic_ptr_type_ok().\nFor a load-acquire that fetches into its own source register (dst_reg ==\nsrc_reg), check_load_mem() overwrites src_reg's type with the type of the\nloaded value, so the subsequent atomic_ptr_type_ok() no longer sees the\nsource pointer and fails to reject the disallowed types (ctx, pkt,\nflow_keys, sock).\n\nSince bpf_convert_ctx_accesses() does not rewrite atomic loads, the raw\naccess to the underlying kernel object is left in place. The destination\ntype is taken from the ctx access itself, so a load-acquire of the sk\nfield of struct __sk_buff for example leaves the register typed as\nPTR_TO_SOCK_COMMON_OR_NULL, which type_is_sk_pointer() does not match\neither, while it actually holds unconverted struct sk_buff bytes. Once\nthe NULL check has passed this is a type confusion, not just a leak of\nkernel data.\n\nValidate src_reg with check_reg_arg() and check the source pointer type\nwith atomic_ptr_type_ok() before the load again, mirroring\ncheck_atomic_rmw(). Out-of-range register numbers are already rejected\nearlier by check_and_resolve_insns() (commit 503d21ef8eac (\"bpf: Do\nregister range validation early\")), and the only exemption there,\nis_stack_arg_ldx(), requires BPF_LDX | BPF_MEM | BPF_DW and thus never\nmatches a BPF_ATOMIC insn. atomic_ptr_type_ok() can therefore not\ndereference register state out of bounds, that is, the out-of-bounds\nread addressed by the Fixes commit below does not reappear (as proven\nalso via selftest)."
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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 a BPF_LOAD_ACQ insn with dst_reg==src_reg in the bytecode bpf_prog_load() copies from bpf(2) BPF_PROG_LOAD (__sys_bpf). do_check_insn()→check_atomic()→check_atomic_load() then lets check_load_mem() overwrite the source type before atomic_ptr_type_ok(); no remote protocol message carries that insn.\nAC:L - The attacker authors a SOCKET_FILTER program that does BPF_LOAD_ACQ of offsetof(__sk_buff, sk) with dst_reg==src_reg (the PTR_TO_CTX). check_load_mem() replaces that register with PTR_TO_SOCK_COMMON_OR_NULL, so type_is_sk_pointer() does not match and atomic_ptr_type_ok() accepts it. No race or uninfluenced layout is required.\nPR:L - bpf_prog_load() allows BPF_PROG_TYPE_SOCKET_FILTER and BPF_PROG_TYPE_CGROUP_SKB without CAP_BPF when sysctl_unprivileged_bpf_disabled is 0; otherwise bpf_token_capable(CAP_BPF) is enough. bpf_token_capable() uses ns_capable() on a delegated token userns, not init-namespace root. verifier_load_acquire.c marks socket load-acquire __success_unpriv.\nUI:N - The attacker loads the program with BPF_PROG_LOAD and runs it via BPF_PROG_TEST_RUN (bpf_prog_test_run_skb on sk_filter_prog_ops) or attaches it to their own socket with setsockopt(SO_ATTACH_BPF)→sk_attach_bpf() and triggers the filter. No other user must mount or open a file.\nS:U - check_atomic_load()'s type confusion and the later interpreter/JIT smp_load_acquire plus bpf_sock_convert_ctx_access loads run in the host kernel that accepted the program. That is in-kernel privilege escalation, not a KVM/Xen guest-to-host escape or IOMMU bypass.\nC:H - bpf_convert_ctx_accesses() does not rewrite BPF_ATOMIC, so load-acquire of offsetof(__sk_buff, sk) reads unconverted sk_buff bytes while the register is typed PTR_TO_SOCK_COMMON_OR_NULL. After a NULL check, later LDX of bpf_sock fields is rewritten by bpf_sock_convert_ctx_access() into struct sock loads against that pointer.\nI:H - The same confused PTR_TO_SOCK_COMMON is accepted as ARG_PTR_TO_SOCK_COMMON by bpf_sk_fullsock and, on CGROUP_SKB, bpf_sk_storage_get, which dereference and update sock-shaped kernel state on an object that is actually raw sk_buff memory. Commit-described verifier type confusion, not a bounded scalar leak.\nA:H - Interpreter BPF_LOAD_ACQ does smp_load_acquire of the unconverted ctx address, and follow-on bpf_sock_convert_ctx_access LDXes dereference that value as struct sock. A non-pointer or unmapped value page-faults in kernel context; the attacker can repeat this via BPF_PROG_TEST_RUN or the attached filter."
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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/verifier.c"
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],
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"versions": [
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{
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"version": "c03bb2fa327e4c25d6c5360a8803a4b1cdc2d0b9",
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"lessThan": "6ee7b00888498cf387dd30729e18a05328b94709",
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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": "c03bb2fa327e4c25d6c5360a8803a4b1cdc2d0b9",
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"lessThan": "422a416041172af1ac610736d5f556d22b31b115",
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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": "c03bb2fa327e4c25d6c5360a8803a4b1cdc2d0b9",
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"lessThan": "b87803391baa7e0bef60549d8841f12e549ad057",
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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/verifier.c"
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],
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"versions": [
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{
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"version": "6.15",
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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": "6.15",
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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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"operator": "OR",
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"negate": false,
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"cpeMatch": [
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"vulnerable": true,
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionStartIncluding": "6.15",
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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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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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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/6ee7b00888498cf387dd30729e18a05328b94709"
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},
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{
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"url": "https://git.kernel.org/stable/c/422a416041172af1ac610736d5f556d22b31b115"
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},
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{
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"url": "https://git.kernel.org/stable/c/b87803391baa7e0bef60549d8841f12e549ad057"
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}
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],
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"title": "bpf: Check load-acquire src ptr type before the load",
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} |