CVE-2026-98803 Linux CVE debrief

Who should care

Linux kernel developers and maintainers, Linux distribution vendors, and users of Linux-based systems that utilize the stmmac driver should assess exposure and prioritize patching to prevent potential denial-of-service conditions and system instability. Affected operators and platforms should review and apply patches, verify driver configurations, and monitor system logs for SMMU translation faults. Vulnerability management and security teams should track

Why it matters

The vulnerability in the Linux kernel's stmmac driver can cause a denial-of-service condition on IOMMU-based platforms. Linux kernel developers and maintainers, Linux distribution vendors, and users of Linux-based systems that utilize the stmmac driver should assess exposure and prioritize patching.

• Denial-of-service condition due to SMMU translation faults
• Potential system crashes or instability
• Increased risk of security incidents due to unpatched vulnerabilities

Technical summary

The Linux kernel's stmmac driver does not properly handle Scatter-Gather for non-split-header frames on certain cores, leading to a DMA translation fault on IOMMU-based platforms. This issue can cause a denial-of-service condition and potentially lead to system crashes or instability. The vulnerability is caused by the stmmac driver not allocating and programming a secondary RX buffer for non-split-header frames on cores that support an independent secondary RX buffer, triggering an SMMU translation fault when the DMA writes to the unmapped secondary buffer address.

Defensive priority

Medium

Recommended defensive actions

• Review and apply the provided patches to the Linux kernel
• Verify the stmmac driver configuration and adjust as needed
• Monitor system logs for SMMU translation faults
• 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 compensating controls for exposed systems while remediation is scheduled and verified

Evidence notes

The vulnerability is caused by the stmmac driver not allocating and programming a secondary RX buffer for non-split-header frames on cores that support an independent secondary RX buffer. This can trigger an SMMU translation fault when the DMA writes to the unmapped secondary buffer address.

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.