CVE-2026-98150 Linux CVE debrief

Who should care

Defenders responsible for Linux kernel security, particularly in environments where untrusted userspace programs may interact with the BPF subsystem, should assess exposure and prioritize patching.

Why it matters

CVE-2026-98150 is a vulnerability in the Linux kernel's BPF subsystem that could lead to kernel errors. Defenders should prioritize verifying the Linux kernel version and applying patches, particularly in environments where untrusted userspace programs may interact with the BPF subsystem.

• Verify Linux kernel version and patch level
• Restrict access to BPF_MAP_TYPE_PERCPU_ARRAY operations
• Monitor for suspicious BPF subsystem activity

Technical summary

The Linux kernel's BPF subsystem had a vulnerability in BPF_F_CPU validation for sparse CPU IDs. The flaw was in the comparison of the CPU ID with num_possible_cpus(), which is the number of possible CPUs rather than a bound on CPU IDs. This led to incorrect validation of CPU IDs, potentially causing kernel errors. A userspace program using raw bpf() syscalls could create a BPF_MAP_TYPE_PERCPU_ARRAY and perform update and lookup operations for each CPU by setting BPF_F_CPU and the CPU ID in the flags, leading to a kernel paging request error. Defenders should prioritize verifying the Linux kernel version and applying patches to address this vulnerability, particularly in environments where untrusted userspace

Defensive priority

Defenders should prioritize verifying the Linux kernel version and applying patches to address this vulnerability, particularly in environments where untrusted userspace programs may interact with the BPF subsystem.

Recommended defensive actions

• Verify Linux kernel version and apply patches
• Restrict access to BPF_MAP_TYPE_PERCPU_ARRAY operations
• Monitor for suspicious BPF subsystem activity
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record and associated sources provide details on the vulnerability, including a description of the issue, affected systems, and potential impacts. However, the corpus does not establish versions, exploitation, impact, or remediation beyond the provided information.

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.