CVE-2026-98647 Linux CVE debrief

Who should care

Defenders responsible for Linux kernel security, BPF administrators, and Linux system maintainers should be aware of this vulnerability and take steps to verify and patch their systems.

Why it matters

A divide-by-zero vulnerability in the Linux kernel's btf_struct_walk() function requires verification and patching of Linux kernel versions, review and securing of BPF configurations, and validation of BPF programs.

• Verification of Linux kernel versions and patch application is required to prevent potential crashes or security issues.
• Review and secure BPF configurations to prevent exploitation.
• Validate BPF programs to ensure they are properly secured.

Technical summary

The Linux kernel's btf_struct_walk() function is vulnerable to a divide-by-zero error when accessing a struct with a flexible array as its last member. This occurs when the offset calculation results in a division by zero, causing the program to crash. The vulnerability can be triggered by a PTR_TO_BTF_ID that is not MEM_ALLOC, such as a plain read of a local kptr stashed in a map from a sleepable program. Defenders should prioritize verifying the Linux kernel version and applying patches to address this vulnerability. They should also review their system's BPF (Berkeley Packet Filter) configurations and ensure that any BPF programs are properly validated and secured.

Defensive priority

Defenders should prioritize verifying the Linux kernel version and applying patches to address this vulnerability. They should also review their system's BPF (Berkeley Packet Filter) configurations and ensure that any BPF programs are properly validated and secured.

Recommended defensive actions

• Verify Linux kernel version and apply patches
• Review and secure BPF configurations
• Validate BPF programs
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up.
• Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance.
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed.
• Check relevant monitoring, detection, and logs for exposed assets that need extra review.

Evidence notes

The vulnerability was resolved in the Linux kernel, and several source references are provided, including kernel.org stable commits. The issue arises from a divide-by-zero error in the btf_struct_walk() function when accessing a struct with a flexible array as its last member. This occurs when the offset calculation results in a division by zero, causing the program to crash. Defenders should verify the Linux kernel version and apply patches to address this vulnerability. They should also review their system's BPF (Berkeley Packet  

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.