What’s Vulnerable › Vulnerabilities

CVE-2026-72006: net/mlx5: free mlx5_st_idx_data on final dealloc

• Severity: unknown
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-15 · updated 2026-08-17

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.

Affected products

• Linux kernel: 6.17 — fixed in 7.2

How to fix

Upgrade to a fixed version: Linux kernel 7.2. Check the vendor advisory for mitigations.

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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