CVE-2026-99062 Linux CVE debrief

Who should care

Defenders managing Linux kernel systems, particularly those utilizing vsock/virtio functionality, should assess exposure and prioritize patching affected versions. Defenders should review system configurations for vsock/virtio usage to identify potentially affected systems. Defenders should prioritize verifying and applying patches for Linux kernel versions affected by this vulnerability, particularly for systems utilizing vsock/virtio functionality.

Why it matters

The vulnerability in the Linux kernel's vsock/virtio implementation could lead to incorrect rx_bytes values, affecting stream receive and buffer tracking. Defenders should prioritize verifying and applying patches for affected Linux kernel versions.

• Verification of Linux kernel versions and patch application is necessary to prevent potential rx_bytes tracking issues.
• Defenders should review system configurations for vsock/virtio usage to identify potentially affected systems.
• Monitoring for potential issues with stream receive and buffer management is recommended.

Technical summary

The Linux kernel's vsock/virtio implementation had a vulnerability in the read_skb() function, where it did not correctly account for unread bytes. This could lead to issues with rx_bytes tracking, affecting stream receive and buffer management. The vulnerability was introduced due to incorrect accounting of unread bytes in the read_skb() function of the Linux kernel's vsock/virtio implementation. This could lead to rx_bytes tracking issues, affecting stream receive and buffer management. The fixed run kept the counter balanced and exposed all queued data immediately.

Defensive priority

Defenders should prioritize verifying and applying patches for Linux kernel versions affected by this vulnerability, particularly for systems utilizing vsock/virtio functionality.

Recommended defensive actions

• Verify Linux kernel versions and apply patches for affected systems
• Review system configurations for vsock/virtio usage
• Monitor for potential rx_bytes tracking issues
• 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.
• Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance.

Evidence notes

The vulnerability was introduced due to incorrect accounting of unread bytes in the read_skb() function of the Linux kernel's vsock/virtio implementation. This could lead to rx_bytes tracking issues, affecting stream receive and buffer management.

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.