CVE-2026-43466
DMA FIFO Desync in Linux Kernel mlx5e Driver
Publication date: 2026-05-08
Last updated on: 2026-05-08
Assigner: kernel.org
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| mlx5 | mlx5e | From 6.13.0-rc5 (inc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-UNKNOWN |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability exists in the Linux kernel's mlx5e network driver related to DMA FIFO synchronization during error recovery.
When a transmit (TX) error completion queue entry (CQE) occurs, a recovery process resets the dma_fifo_cc counter to zero but does not reset the dma_fifo_pc counter. This causes a desynchronization between the DMA FIFO producer and consumer pointers.
After recovery, the producer continues to push new DMA entries at the old dma_fifo_pc position, while the consumer reads from position zero, leading to unmapping of stale DMA addresses from before the recovery.
The fix removes the unnecessary reset of dma_fifo_cc to zero, aligning with the fact that at reset all work queue entries have been flushed and the counters are already synchronized.
How can this vulnerability impact me? :
This vulnerability can cause improper handling of DMA memory mappings during error recovery in the mlx5e network driver.
Specifically, it may lead to unmapping of stale DMA addresses, which could cause system instability, warnings, or crashes related to memory management in the network driver.
Such issues could affect network performance or reliability on systems using the affected driver.
How can this vulnerability be detected on my network or system? Can you suggest some commands?
This vulnerability manifests as a WARNING message in the kernel logs related to DMA unmapping in the mlx5e driver. Detection involves monitoring system logs for the specific warning:
- WARNING: CPU: 0 PID: 0 at drivers/iommu/dma-iommu.c:1240 iommu_dma_unmap_page+0x79/0x90
You can detect this issue by checking the kernel log messages using commands such as:
- dmesg | grep -i iommu_dma_unmap_page
- journalctl -k | grep -i iommu_dma_unmap_page
- journalctl -k | grep -i mlx5e
These commands help identify the warning messages indicating the DMA FIFO desynchronization issue in the mlx5e driver.
What immediate steps should I take to mitigate this vulnerability?
The vulnerability is fixed by a kernel patch that corrects the DMA FIFO counters reset behavior in the mlx5e driver. Immediate mitigation steps include:
- Update your Linux kernel to a version that includes the fix for this vulnerability (post 6.13.0-rc5 or the version containing the patch).
- Monitor kernel logs for the warning message to detect if the issue is occurring.
- If updating the kernel immediately is not possible, consider disabling or limiting the use of the mlx5e driver or related hardware until the patch can be applied.
Since this is a software-level fix in the kernel driver, applying the updated kernel is the recommended and effective mitigation.
How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:
The provided information about CVE-2026-43466 does not include any details regarding its impact on compliance with common standards and regulations such as GDPR or HIPAA.