CVE-2026-43371 net: macb: Shuffle the tx ring before enabling tx

What is CVE-2026-43371?

CVE-2026-43371 is a medium-severity memory corruption vulnerability in Linux kernel, published on 8 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

In the Linux kernel, the following vulnerability has been resolved:

net: macb: Shuffle the tx ring before enabling tx

Quanyang observed that when using an NFS rootfs on an AMD ZynqMp board, the rootfs may take an extended time to recover after a suspend. Upon investigation, it was determined that the issue originates from a problem in the macb driver.

According to the Zynq UltraScale TRM [1], when transmit is disabled, the transmit buffer queue pointer resets to point to the address specified by the transmit buffer queue base address register.

In the current implementation, the code merely resets `queue->tx_head` and `queue->tx_tail` to '0'. This approach presents several issues:

- Packets already queued in the tx ring are silently lost, leading to memory leaks since the associated skbs cannot be released.

- Concurrent write access to `queue->tx_head` and `queue->tx_tail` may occur from `macb_tx_poll()` or `macb_start_xmit()` when these values are reset to '0'.

- The transmission may become stuck on a packet that has already been sent out, with its 'TX_USED' bit set, but has not yet been processed. However, due to the manipulation of 'queue->tx_head' and 'queue->tx_tail', `macb_tx_poll()` incorrectly assumes there are no packets to handle because `queue->tx_head == queue->tx_tail`. This issue is only resolved when a new packet is placed at this position. This is the root cause of the prolonged recovery time observed for the NFS root filesystem.

To resolve this issue, shuffle the tx ring and tx skb array so that the first unsent packet is positioned at the start of the tx ring. Additionally, ensure that updates to `queue->tx_head` and `queue->tx_tail` are properly protected with the appropriate lock.

[1] https://docs.amd.com/v/u/en-US/ug1085-zynq-ultrascale-trm

Weakness: CWE-401

Which versions are affected by CVE-2026-43371?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2026-43371?

Apply the vendor's patch.

Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.

Is CVE-2026-43371 being exploited?

There is no known exploitation of CVE-2026-43371 in the wild and no public exploit code.

Other vulnerabilities in Linux kernel

• CVE-2026-53266 Linux Kernel Out-of-Bounds Write Exploited High 8.8
• CVE-2013-6282 Linux Kernel Improper Input Validation Exploited High 8.8
• CVE-2022-0185 Linux Kernel Heap-Based Buffer Overflow Exploited High 8.4
• CVE-2013-2094 Linux Kernel Privilege Escalation Exploited High 8.4
• CVE-2026-53362 Linux Kernel Unspecified Exploited High 7.8

All Linux kernel vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as AZL-110420, BELL-CVE-2026-43371, DEBIAN-CVE-2026-43371, GHSA-53cc-xh3p-4x9v, ROOT-OS-UBUNTU-2404-CVE-2026-43371, UBUNTU-CVE-2026-43371.