CVE-2026-99078 Linux CVE debrief

Who should care

Linux kernel maintainers, system administrators, and security teams responsible for managing Linux-based systems, particularly those using AF_XDP on striding RQ, should assess exposure and prioritize patching.

Why it matters

This vulnerability in the Linux kernel's net/mlx5e component can lead to system instability or potential code execution, requiring prompt assessment and patching by Linux kernel maintainers, system administrators, and security teams.

• Denial-of-service due to potential buffer release issues.
• Verification of patch application and system configuration required.
• Potential for arbitrary code execution if exploited, requiring immediate attention.

Technical summary

The Linux kernel's net/mlx5e component has a vulnerability that can cause stale XSK buffer release on MPWQE refill retry. This issue arises from the deferral of XSK buffer release until an MPWQE is refilled. If XSK allocation returns -ENOMEM, actual_wq_head is not advanced, and a later NAPI poll retries the same WQE. The mlx5e_free_rx_mpwqe() function leaves each released slot marked as releasable, allowing xsk_buff_free() to be called again through stale pointers after the frames have returned to the XSK pool and been reallocated.

Defensive priority

High

Recommended defensive actions

• Review and apply patches from the Linux kernel maintainers.
• Update to a fixed version of the Linux kernel.
• Monitor system logs for potential denial-of-service attempts.
• Verify patch application and system configuration.
• 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 source item provide details on the vulnerability, including its description and affected versions. However, the corpus does not establish versions, exploitation, impact, or remediation, which require verification from the supplied official sources.

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.