{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-98150", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-25T10:25:14.320Z", "datePublished": "2026-09-25T10:36:22.774Z", "dateUpdated": "2026-09-25T14:42:12.855Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-09-25T14:42:12.855Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix BPF_F_CPU validation for sparse CPU IDs\n\nBPF_F_CPU stores the target CPU ID in the upper 32 bits of the map\noperation flags. bpf_map_check_op_flags() currently compares that ID\nwith num_possible_cpus(), which is the number of possible CPUs rather\nthan a bound on CPU IDs.\n\nOn an arm64 QEMU guest with a CPU device-tree hole, the possible CPU\nmask was 0,2-3. A userspace program using raw bpf() syscalls creates\na BPF_MAP_TYPE_PERCPU_ARRAY and performs update and lookup operations\nfor each CPU by setting BPF_F_CPU and the CPU ID in the flags.\n\nWith the old check, CPU 1 is incorrectly accepted while valid CPU 3 is\nrejected with -ERANGE. The CPU 1 update then reaches the per-CPU map\naccess path and triggers:\n\n Unable to handle kernel paging request at virtual address ...\n pc : __pi_memcpy_generic+0x5c/0x22c\n lr : bpf_percpu_array_update+0x2dc/0x2e8\n Call trace:\n __pi_memcpy_generic\n bpf_map_update_value\n map_update_elem\n __sys_bpf\n\nCheck the CPU ID against nr_cpu_ids and cpu_possible() instead. This\nrejects CPU IDs outside the valid range and CPUs absent from the\npossible mask, while allowing valid sparse CPU IDs." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The out-of-range CPU ID arrives in attr->flags of the local bpf(2) BPF_MAP_UPDATE_ELEM/LOOKUP_ELEM syscall (map_update_elem/map_lookup_elem -> bpf_map_check_op_flags); no network or adjacent protocol carries it.\nAC:H - The check only lets through a CPU ID in a hole of the possible-CPU mask (e.g. 0,2-3 on arm64 device-tree systems). That topology comes from firmware/hardware and the attacker can't create it. It also needs a permissive BPF setup, and where the stray per_cpu_ptr() lands (unmapped init memory vs mapped .data) depends on percpu allocator placement.\nPR:L - BPF_MAP_TYPE_PERCPU_ARRAY/PERCPU_HASH are in map_create()'s unprivileged list when unprivileged_bpf_disabled=0 or with a delegated BPF token, and map_update_elem/map_lookup_elem check only FMODE_CAN_WRITE/READ on the map fd, not a capability.\nUI:N - The attacker creates or opens the per-CPU map and issues the update/lookup with BPF_F_CPU and a hole CPU ID entirely on their own; no other user acts.\nS:U - The bad access corrupts or reads kernel memory within the same kernel security authority; no VM, IOMMU or sandbox boundary is crossed.\nC:H - bpf_percpu_array_copy() copies value_size bytes from per_cpu_ptr(pptr, cpu) for a missing CPU whose __per_cpu_offset is 0, i.e. from a stray kernel address, back to userspace via BPF_MAP_LOOKUP_ELEM, and the attacker can repeat it.\nI:H - bpf_percpu_array_update() does copy_map_value() of attacker-supplied value bytes to per_cpu_ptr(pptr, cpu) for the missing CPU. That is an out-of-bounds write of controlled data to an address outside any valid per-CPU unit, which can land in kernel .data past __init_end.\nA:H - As the fix commit shows, the update faults in __pi_memcpy_generic from bpf_percpu_array_update on unmapped memory (the freed/vunmapped __init region on arm64), causing a kernel oops." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "include/linux/bpf.h" ], "versions": [ { "version": "2b421662c7887a0649fe409155a1f101562d0fa9", "lessThan": "bdc5941f6eeef90b76a07fd8ca38ac1933ba2195", "status": "affected", "versionType": "git" }, { "version": "2b421662c7887a0649fe409155a1f101562d0fa9", "lessThan": "ed54bf564ac52699cf4def3d0c2125d493e756f9", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "include/linux/bpf.h" ], "versions": [ { "version": "7.0", "status": "affected" }, { "version": "0", "lessThan": "7.0", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.7", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.3-rc2", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "7.0", "versionEndExcluding": "7.2.7" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "7.0", "versionEndExcluding": "7.3-rc2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/bdc5941f6eeef90b76a07fd8ca38ac1933ba2195" }, { "url": "https://git.kernel.org/stable/c/ed54bf564ac52699cf4def3d0c2125d493e756f9" } ], "title": "bpf: Fix BPF_F_CPU validation for sparse CPU IDs", "x_generator": { "engine": "bippy-1.2.0" } } } }