{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-93112", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-17T16:02:15.086Z", "datePublished": "2026-09-17T16:11:21.122Z", "dateUpdated": "2026-10-19T09:05:45.809Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T09:05:45.809Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Require a BPF cpumask for bpf_cpumask_populate()\n\nbpf_cpumask_populate() writes to its destination with bitmap_copy(), but\nthe destination is typed as struct cpumask *. That allows the verifier to\naccept borrowed cpumask pointers returned by read-only kfuncs, such as\nscx_bpf_get_online_cpumask(), as a writable destination.\n\nMake the destination a struct bpf_cpumask * so populate follows the same\nownership rule as the other mutating cpumask kfuncs. Query kfuncs continue\nto accept const struct cpumask * inputs." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H", "baseScore": 7.1, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - bpf_cpumask_populate() is a kfunc on BPF_PROG_TYPE_SYSCALL/TRACING/STRUCT_OPS programs loaded via bpf(BPF_PROG_LOAD); the src bitmap is program-local memory, and a SYSCALL program runs it through BPF_PROG_TEST_RUN (bpf_prog_test_run_syscall). Those bits do not arrive in a network protocol message.\nAC:L - A program can call scx_bpf_get_online_cpumask() then bpf_cpumask_populate() in one path; process_kf_arg_ptr_to_btf_id() does not require strict matching here, so the borrowed struct cpumask * is accepted and bitmap_copy() runs with no race or layout dependency.\nPR:L - bpf_prog_load() of BPF_PROG_TYPE_SYSCALL needs only bpf_token_capable(CAP_BPF) (SYSCALL is not in is_perfmon_prog_type); TRACING/STRUCT_OPS also need CAP_PERFMON. bpf_token_capable() checks token->userns, so a delegated BPF token grants this to userns root rather than init-namespace root.\nUI:N - The attacker loads their own program and either BPF_PROG_TEST_RUN it or fork() to fire their tp_btf/task_newtask hook; no other user must mount, open a file, or otherwise interact.\nS:U - bitmap_copy() overwrites host kernel objects (__cpu_online_mask from scx_bpf_get_online_cpumask(), or task_struct.cpus_mask via cpus_ptr) in the same kernel; this is not a KVM/Xen escape or IOMMU bypass.\nC:N - bpf_cpumask_populate() only bitmap_copy()s the caller-supplied src buffer into the destination mask; it does not read kernel memory back to the program or otherwise disclose confidential data.\nI:H - The destination was typed struct cpumask * rather than struct bpf_cpumask *, so bitmap_copy() writes attacker-controlled bits into borrowed kernel masks such as cpu_online_mask from scx_bpf_get_online_cpumask() or task->cpus_ptr, which bpf_cpumask_set_cpu() would reject.\nA:H - Overwriting writable __cpu_online_mask forges the set walked by for_each_online_cpu(), so the scheduler IPIs or indexes per-CPU state for offline CPUs or sees num_online_cpus()==0, causing a kernel oops or hang." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "kernel/bpf/cpumask.c", "tools/sched_ext/include/scx/compat.bpf.h" ], "versions": [ { "version": "950ad93df2fce70445e655ed2e74f5c1a8653ab2", "lessThan": "0cfc9348a045da64955af2dd6902e66dfc7d6469", "status": "affected", "versionType": "git" }, { "version": "950ad93df2fce70445e655ed2e74f5c1a8653ab2", "lessThan": "b7e2a5c6519adc73be55c3de2cb545e095a0fbc5", "status": "affected", "versionType": "git" }, { "version": "950ad93df2fce70445e655ed2e74f5c1a8653ab2", "lessThan": "8740156ad33be5071b588b594c55f279457f667c", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "kernel/bpf/cpumask.c", "tools/sched_ext/include/scx/compat.bpf.h" ], "versions": [ { "version": "6.15", "status": "affected" }, { "version": "0", "lessThan": "6.15", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.52", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.6", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.3", "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": "6.15", "versionEndExcluding": "6.18.52" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.15", "versionEndExcluding": "7.2.6" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.15", "versionEndExcluding": "7.3" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/0cfc9348a045da64955af2dd6902e66dfc7d6469" }, { "url": "https://git.kernel.org/stable/c/b7e2a5c6519adc73be55c3de2cb545e095a0fbc5" }, { "url": "https://git.kernel.org/stable/c/8740156ad33be5071b588b594c55f279457f667c" } ], "title": "bpf: Require a BPF cpumask for bpf_cpumask_populate()", "x_generator": { "engine": "bippy-1.2.0" } } } }