CVE-2026-98647

CVE Details

Release Date:2026-10-18
Impact:Moderate What is this?

Description


In the Linux kernel, the following vulnerability has been resolved: bpf: Fix divide-by-zero in btf_struct_walk() When an access goes past the struct and the last member is a flexible array, btf_struct_walk() folds the offset back into a single element with (off - moff) % t->size, but never checks that the element type has a size. BTF takes an empty struct, so this in program BTF /* event could be empty */ struct event { #ifdef HAVE_TIMESTAMP __u64 ts; #endif }; struct batch { int nr; struct event events[]; }; divides by zero at prog load time. Getting there needs a PTR_TO_BTF_ID that is not MEM_ALLOC, e.g. a plain read of a local kptr stashed in a map from a sleepable program. Oops: divide error: 0000 [#1] SMP KASAN PTI RIP: 0010:btf_struct_walk+0x53f/0x1570 Call Trace: btf_struct_access+0x42a/0xcd0 check_ptr_to_btf_access+0x4dc/0x1160 check_mem_access+0x3a45/0x8740 check_load_mem+0x36a/0xd10 do_check_common+0x3ef0/0xb210 bpf_check+0x6d3b/0x8580 bpf_prog_load+0xf7c/0x2720 __sys_bpf+0xa83/0x3690 __x64_sys_bpf+0xc7/0x150 x64_sys_call+0x1f3f/0x27e0 do_syscall_64+0xe5/0x610 entry_SYSCALL_64_after_hwframe+0x76/0x7e Reject a zero-sized element type. The fixed array path in the same function already bails out on the same thing: btf_struct_walk() ... /* skip empty array */ if (moff == mtrue_end) continue; msize /= total_nelems;

See more information about CVE-2026-98647 from MITRE CVE dictionary and NIST NVD


NOTE: The following CVSS metrics and score provided are preliminary and subject to review.


CVSS v3 metrics

Base Score: 5.5
Vector String: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Version: 3.1
Attack Vector: Local
Attack Complexity: Low
Privileges Required: Low
User Interaction: None
Scope: Unchanged
Confidentiality Impact: None
Integrity Impact: None
Availability Impact: High

Errata information


PlatformErrataRelease Date
Oracle Linux version 10 (kernel-uek) ELSA-2026-5005722026-11-02
Oracle Linux version 8 (kernel-uek) ELSA-2026-5005742026-11-02
Oracle Linux version 9 (kernel-uek) ELSA-2026-5005722026-11-02
Oracle Linux version 9 (kernel-uek) ELSA-2026-5005742026-11-02


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