{ "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": "2026-10-21T12:50:30.155Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-21T12:50:30.155Z" }, "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": "86bbaf9e6e4fa6c0dfb352e9e11fae328069233a", "status": "affected", "versionType": "git" }, { "version": "dfab99df147b0d364f0c199f832ff2aedfb2265a", "lessThan": "e4ab436d5ba61e4910fd49d24bb64ddb34d493d6", "status": "affected", "versionType": "git" }, { "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": "6.12.114", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.57", "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": "6.7", "versionEndExcluding": "6.12.114" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.7", "versionEndExcluding": "6.18.57" }, { "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" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/86bbaf9e6e4fa6c0dfb352e9e11fae328069233a" }, { "url": "https://git.kernel.org/stable/c/e4ab436d5ba61e4910fd49d24bb64ddb34d493d6" }, { "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" } } } }