{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-90217","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-09-11T19:38:34.793Z","datePublished":"2026-09-17T16:07:29.409Z","dateUpdated":"2026-09-18T17:53:48.672Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-09-18T17:53:48.672Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Compare iterator types during state pruning\n\nAn iterator stack slot can be MEM_RCU or PTR_UNTRUSTED. These states\nmust not be equal, or the verifier can prune an unsafe path.\n\nCompare the pointer type for STACK_ITER slots."}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - The attacker-controlled input is the BPF instruction stream copied in bpf_prog_load() from bpf(2) BPF_PROG_LOAD (__sys_bpf). bpf_check() then stacksafe() treats STACK_ITER slots with MEM_RCU and PTR_UNTRUSTED as equal; that bytecode is local syscall input, not a remote protocol payload.\nAC:L - The attacker authors both verifier paths as in iter_tasks_rcu_state_pruning: bpf_iter_task_new under bpf_rcu_read_lock, then a bpf_get_prandom_u32 branch that nested-lock/unlock (MEM_RCU) or unlock/relock (PTR_UNTRUSTED) before bpf_iter_task_next. Both sides and the branch are attacker-controlled; no victim timing is required.\nPR:L - add_subprog_and_kfunc() rejects kfunc calls unless env->bpf_capable. bpf_iter_task_new and bpf_iter_css_new are kfuncs; BPF_PROG_TYPE_SYSCALL (always sleepable) needs only bpf_token_capable(CAP_BPF). bpf_token_capable() uses ns_capable() on a delegated token userns, so this is not init-namespace root.\nUI:N - The attacker loads the crafted sleepable program with BPF_PROG_LOAD and executes it via BPF_PROG_TEST_RUN (bpf_prog_test_run_syscall) or by attaching their own fentry.s; no other user must mount a filesystem, open a file, or cooperate.\nS:U - A pruned bpf_iter_task_next() walks host task_struct lists in the same kernel that loaded the program. That is in-kernel use-after-free and privilege escalation, not a KVM/Xen guest-to-host escape or IOMMU bypass.\nC:H - After the pruned unlock/relock gap, bpf_iter_task_next() returns kit->pos from bpf_iter_task_kern, a task_struct * that may already have been RCU-freed. The program can read BTF fields of that dangling pointer, so the UAF is an arbitrary kernel disclosure.\nI:H - bpf_iter_task_next() then calls next_task()/__next_thread() (list_entry_rcu on tasks.next and thread_node) using the dangling kit->pos. Walking attacker-reclaimed task_struct list nodes is a kernel write primitive; UAF and iterator type confusion are Integrity High.\nA:H - Using the untrusted STACK_ITER after the RCU gap makes next_task() or css_next_descendant_*() dereference a freed task_struct or cgroup_subsys_state, causing a kernel oops or panic even when the UAF is not fully exploited."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/bpf/states.c"],"versions":[{"version":"dfab99df147b0d364f0c199f832ff2aedfb2265a","lessThan":"6424b9cde9edc7f2098115bbfd1ee3d84a958380","status":"affected","versionType":"git"},{"version":"dfab99df147b0d364f0c199f832ff2aedfb2265a","lessThan":"83608e303b95d07afba1c15da0b5d9e513c2f15a","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/states.c"],"versions":[{"version":"6.7","status":"affected"},{"version":"0","lessThan":"6.7","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":"6.7","versionEndExcluding":"7.2.6"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.7","versionEndExcluding":"7.3-rc1"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/6424b9cde9edc7f2098115bbfd1ee3d84a958380"},{"url":"https://git.kernel.org/stable/c/83608e303b95d07afba1c15da0b5d9e513c2f15a"}],"title":"bpf: Compare iterator types during state pruning","x_generator":{"engine":"bippy-1.2.0"}}}}