CVE-2026-93138 Linux CVE debrief

Who should care

Linux kernel maintainers, Linux distribution maintainers, and users of Linux kernels should assess their exposure to this vulnerability and verify the presence of the fix in their kernel versions.

Why it matters

A race condition vulnerability in the Linux kernel's bpf_get_btf_vmlinux function has been resolved. Linux kernel maintainers and users should assess exposure and verify the presence of the fix in their kernel versions.

• Verification of Linux kernel versions and configurations is necessary to determine exposure.
• Applying patches or updates to the Linux kernel may be necessary to fix the vulnerability.
• Monitoring Linux kernel updates and applying patches as necessary can help prevent exploitation.

Technical summary

The Linux kernel's bpf_get_btf_vmlinux function has a race condition vulnerability that has been resolved. The vulnerability arises from the lazy parsing of vmlinux BTF under the bpf_verifier_lock and publishing the result through a plain store. This could lead to a concurrent first-time caller observing the pointer before the parsed contents are visible on a weakly ordered architecture. The fix involves publishing the pointer with smp_store_release() and reading it on the fast path with smp_load_acquire().

Defensive priority

Linux kernel maintainers and users should assess exposure and verify the presence of the fix in their kernel versions.

Recommended defensive actions

• Assess exposure by checking Linux kernel versions and configurations.
• Verify the presence of the fix in the kernel versions used.
• Monitor Linux kernel updates and apply patches as necessary.
• 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 NVD entry provide details on the vulnerability, including its description and CVSS score. Linux kernel maintainers and users should assess exposure and verify the presence of the fix in their kernel versions. The vulnerability arises from the lazy parsing of vmlinux BTF under the bpf_verifier_lock and publishing the result through a plain store. This could lead to a concurrent first-time caller observing the pointer before the parsed contents are visible on a weakly ordered architecture. The fix involves publishing

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.