CVE-2026-43061: Linux Kernel

Medium severity, CVSS 5.5. EPSS: 0.1% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: serial: 8250: Fix TX deadlock when using DMA `dmaengine_terminate_async` does not guarantee that the `__dma_tx_complete` callback will run. The callback is currently the only place where `dma->tx_running` gets cleared. If the transaction is canceled and the callback never runs, then `dma->tx_running` will never get cleared and we will never schedule new TX DMA transactions again. This change makes it so we clear `dma->tx_running` after we terminate the DMA transaction. This is "safe" because `serial8250_tx_dma_flush` is holding the UART port lock. The first thing the callback does is also grab the UART port lock, so access to `dma->tx_running` is serialized.

Affected products

• Linux Linux Kernel: from 5.4.291, before 5.5 (fixed in 5.5); from 5.10.235, before 5.10.253 (fixed in 5.10.253); from 5.15.179, before 5.15.203 (fixed in 5.15.203); from 6.1.129, before 6.1.167 (fixed in 6.1.167); from 6.6.79, before 6.6.130 (fixed in 6.6.130); from 6.12.16, before 6.12.78 (fixed in 6.12.78); …

Published 2026-05-05. Last modified 2026-06-17.