---
id: CVE-2026-72072
title: 'net/mlx5e: macsec: fix use-after-free of metadata_dst on RX SC delete'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  net/mlx5e: macsec: fix use-after-free of metadata_dst on RX SC delete

  When an offloaded MACsec RX SC is deleted, macsec_del_rxsc_ctx() freed
  the per-SC metadata_dst wi…
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cvssSource: cna
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= b7c9400cbc48c3713190b3bce4e0c87e924e4104 <
    b1a4d0c568bbb52c7c04f4fce3c097dae89ed6cb
  - >-
    Linux >= b7c9400cbc48c3713190b3bce4e0c87e924e4104 <
    218cc15a4c907659ad4b0e68c535c61594311205
  - >-
    Linux >= b7c9400cbc48c3713190b3bce4e0c87e924e4104 <
    4a5073b7b30243658f58b2d2d35a823da7fd34d9
  - >-
    Linux >= b7c9400cbc48c3713190b3bce4e0c87e924e4104 <
    ed3cc4218070d6b98bf5fb456dccae424fd38c4f
  - >-
    Linux >= b7c9400cbc48c3713190b3bce4e0c87e924e4104 <
    088873af13590ebde10de2ade847f57a05ec61c6
  - >-
    Linux >= b7c9400cbc48c3713190b3bce4e0c87e924e4104 <
    de74d8fd10291763d97b218f09adcc7513c975e4
  - Linux 6.1
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-16T15:51:23.230539Z'
published: '2026-08-15'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T15:53:19.757Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-72072'
references:
  - url: 'https://git.kernel.org/stable/c/b1a4d0c568bbb52c7c04f4fce3c097dae89ed6cb'
  - url: 'https://git.kernel.org/stable/c/218cc15a4c907659ad4b0e68c535c61594311205'
  - url: 'https://git.kernel.org/stable/c/4a5073b7b30243658f58b2d2d35a823da7fd34d9'
  - url: 'https://git.kernel.org/stable/c/ed3cc4218070d6b98bf5fb456dccae424fd38c4f'
  - url: 'https://git.kernel.org/stable/c/088873af13590ebde10de2ade847f57a05ec61c6'
  - url: 'https://git.kernel.org/stable/c/de74d8fd10291763d97b218f09adcc7513c975e4'
tags:
  - cve.org
epss: 0.00171
epssPercentile: 0.06061
ingestedAt: '2026-10-16T17:24:46.876Z'
---

## Overview

In the Linux kernel, the following vulnerability has been resolved:

net/mlx5e: macsec: fix use-after-free of metadata_dst on RX SC delete

When an offloaded MACsec RX SC is deleted, macsec_del_rxsc_ctx() freed
the per-SC metadata_dst with metadata_dst_free(), which kfree()s the
object unconditionally and ignores the dst reference count. The RX
datapath in mlx5e_macsec_offload_handle_rx_skb() looks up the SC under
rcu_read_lock() via xa_load(), takes a reference with dst_hold() and
attaches the dst to the skb with skb_dst_set(). A reader that already
obtained the rx_sc pointer can race with the delete path and operate on
freed memory.

Fix the owner side by dropping the reference with dst_release() instead
of freeing unconditionally, and convert the RX datapath to
dst_hold_safe() so a reader racing the SC delete cannot attach a dst
whose last reference was just dropped; only attach it when a reference
was actually taken.

mlx5e_macsec_add_rxsc() also published sc_xarray_element via xa_alloc()
before rx_sc->md_dst was allocated and initialised, so a datapath reader
that looked the SC up by fs_id could observe rx_sc with md_dst still
NULL or, on weakly-ordered architectures, a non-NULL md_dst pointer
whose contents were not yet visible. NULL-check the xa_load() result and
md_dst on the datapath, and reorder add_rxsc() so the xa_alloc() publish
happens only after md_dst is fully initialised; the xarray RCU publish
then pairs with the rcu_read_lock()/xa_load() in the datapath.

Note: macsec_del_rxsc_ctx() also kfree()s rx_sc->sc_xarray_element
without an RCU grace period while the same datapath reads it under
rcu_read_lock(); that is a separate pre-existing issue left to a
follow-up patch.

Found by 0sec automated security-research tooling (https://0sec.ai).

## Affected

- `Linux >= b7c9400cbc48c3713190b3bce4e0c87e924e4104 < b1a4d0c568bbb52c7c04f4fce3c097dae89ed6cb`
- `Linux >= b7c9400cbc48c3713190b3bce4e0c87e924e4104 < 218cc15a4c907659ad4b0e68c535c61594311205`
- `Linux >= b7c9400cbc48c3713190b3bce4e0c87e924e4104 < 4a5073b7b30243658f58b2d2d35a823da7fd34d9`
- `Linux >= b7c9400cbc48c3713190b3bce4e0c87e924e4104 < ed3cc4218070d6b98bf5fb456dccae424fd38c4f`
- `Linux >= b7c9400cbc48c3713190b3bce4e0c87e924e4104 < 088873af13590ebde10de2ade847f57a05ec61c6`
- `Linux >= b7c9400cbc48c3713190b3bce4e0c87e924e4104 < de74d8fd10291763d97b218f09adcc7513c975e4`
- `Linux 6.1`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.