---
id: CVE-2026-98014
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  net/mlx5: E-Switch, prevent mc_list repopulation during vport disable

  In mlx5_esw_vport_disable(), move esw_apply_vport_rx_mode() ahead
  of esw_vport_change_handle_lock…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  net/mlx5: E-Switch, prevent mc_list repopulation during vport disable

  In mlx5_esw_vport_disable(), move esw_apply_vport_rx_mode() ahead
  of esw_vport_change_handle_lock…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 922f56e9a795d6f3dd72d3428ebdd7ee040fa855 <
    69904608e25e8ba58111aadd9210892cf3876201
  - >-
    Linux >= 922f56e9a795d6f3dd72d3428ebdd7ee040fa855 <
    72cfcb79026cffb6490f5044153a841d360b0cfc
  - >-
    Linux >= 922f56e9a795d6f3dd72d3428ebdd7ee040fa855 <
    668e050429c7ca688cf4e7112f97f0cd269d446b
  - >-
    Linux >= 922f56e9a795d6f3dd72d3428ebdd7ee040fa855 <
    c0c6f4ba8a37688f7b4d4044898d88f0450d44c2
  - Linux 18cead61e437f4c7898acca0a5f3df12f801d97f
  - Linux 4df1f2d36bdc9a368650bf14b9097c555e95f71d
  - Linux 63546395a0e6ac264f78f65218086ce6014b4494
  - Linux 6f5780536181d1d0d09a11a1bc92f22e143447e2
  - Linux >= 5.10.177 < 5.11
  - Linux >= 5.15.105 < 5.16
  - Linux >= 6.1.22 < 6.2
  - Linux >= 6.2.9 < 6.3
  - Linux 6.3
published: '2026-09-25'
updated: '2026-09-25'
sourceUpdated: '2026-09-25T11:17:29.767'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-98014'
references:
  - url: 'https://git.kernel.org/stable/c/668e050429c7ca688cf4e7112f97f0cd269d446b'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/69904608e25e8ba58111aadd9210892cf3876201'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/72cfcb79026cffb6490f5044153a841d360b0cfc'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/c0c6f4ba8a37688f7b4d4044898d88f0450d44c2'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-25T11:06:38.857Z'
---

## Overview

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

net/mlx5: E-Switch, prevent mc_list repopulation during vport disable

In mlx5_esw_vport_disable(), move esw_apply_vport_rx_mode() ahead
of esw_vport_change_handle_locked() so vport->allmulti_rule is
NULL before the change handler observes it.

During FW-fatal recovery the disable runs while dev->state ==
INTERNAL_ERROR. The promisc query inside esw_update_vport_rx_mode()
fails and returns early, leaving vport->allmulti_rule intact, so
esw_update_vport_mc_promisc() runs and adds MLX5_ACTION_ADD entries
to vport->mc_list whose flow rules are then installed in the FDB
by esw_add_mc_addr(). esw_destroy_legacy_table() tears down the
FDB with those refs still held, corrupting the sub-tree and
leaving dangling flow_rule pointers in vport->mc_list.

Two-stage failure on `echo 1 > /sys/bus/pci/devices/<bdf>/reset`:

  refcount_t: underflow; use-after-free.
   tree_put_node+0xef/0x110 [mlx5_core]
   clean_tree+0x44/0xd0 [mlx5_core] (x5)
   mlx5_fs_core_cleanup+0x57/0x1c0 [mlx5_core]
   mlx5_unload+0x65/0xd0 [mlx5_core]
   ... mlx5_health_try_recover

  BUG: unable to handle page fault for address: 0000000003000055
   down_write+0x1c/0x60
   mlx5_del_flow_rules+0x33/0x1f0 [mlx5_core]
   esw_del_mc_addr+0x7b/0x170 [mlx5_core]
   esw_apply_vport_addr_list+0x56/0xf0 [mlx5_core]
   esw_vport_change_handle_locked+0x28b/0x310 [mlx5_core]
   mlx5_esw_vport_enable+0x270/0x4a0 [mlx5_core]
   ... mlx5_load ... mlx5_health_try_recover

esw_apply_vport_rx_mode(false, false) clears vport->allmulti_rule
via its local state machine even when the FW del fails. With the
rule NULL the !IS_ERR_OR_NULL(allmulti_rule) gate in the change
handler closes, no rules are installed during disable, and the
reload starts with a clean mc_list.

## Remediation

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