Impact
A bug in the Linux macb driver causes the transmit ring to be incorrectly reset to zero when transmit is disabled. This results in packets already queued in the tx ring being silently lost, leading to memory leaks of skb structures, and can cause the transmitter to become stuck on a packet that has already been sent but not yet processed. The improper manipulation of queue pointers also allows concurrent write access to the head and tail indices, creating a race condition that further degrades the reliability of network transmission. These issues collectively manifest as an extended recovery time after a system suspend, and they can cause denial of Service for applications relying on network I/O, particularly for NFS root filesystems on embedded devices.
Affected Systems
The vulnerability affects all machines running the Linux kernel with the macb driver enabled, with a pronounced impact on AMD Zynq UltraScale devices that use a Network File System root filesystem. Any system that performs suspend/resume operations and relies on the macb Ethernet controller while the kernel version predates the patch will be affected. This includes embedded boards and appliances that implement the ZynqMP SoC and run an unpatched Linux distribution.
Risk and Exploitability
The CVSS score is not provided, and the EPSS metric is unavailable, so the precise likelihood of exploitation cannot be quantified. The CVE has not been listed in the CISA KEV catalog, implying no known active exploitation at the time of analysis. Reasoning about the attack vector, a local or privileged user could trigger the defect by initiating a suspend/resume cycle or by forcing a transmit disable/reset sequence, potentially leading to a service interruption. Since the flaw is tied to driver internals and requires control over hardware initialization, it is unlikely to be exploitable from unprivileged remote access, but could be leveraged by a disgruntled insider or through firmware updates.
OpenCVE Enrichment