{"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":"2026-09-18T17:56:00.309Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-09-18T17:56:00.309Z"},"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-rc1","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-rc1"}]}]}],"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"}}}}