---
id: CVE-2026-64190
title: 'net: team: fix NULL pointer dereference in team_xmit during mode change'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  net: team: fix NULL pointer dereference in team_xmit during mode change

  __team_change_mode() clears team->ops with memset() before restoring
  safe dummy handlers via te…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 3d249d4ca7d0ed6629a135ea1ea21c72286c0d80 <
    9486377e5e971988a3add171c398eb654a866fab
  - >-
    Linux >= 3d249d4ca7d0ed6629a135ea1ea21c72286c0d80 <
    cde5c7f0286c4203d0abc7248201542aa8bf33bb
  - >-
    Linux >= 3d249d4ca7d0ed6629a135ea1ea21c72286c0d80 <
    03e9405c518c4d61f28079492f252d6d4e2bac5c
  - >-
    Linux >= 3d249d4ca7d0ed6629a135ea1ea21c72286c0d80 <
    25fe708bbc59289d3d1ea4b126fbc1b460a072a5
  - Linux 3.3
published: '2026-07-20'
updated: '2026-10-21'
sourceUpdated: '2026-10-21T12:43:10.158Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-64190'
references:
  - url: 'https://git.kernel.org/stable/c/9486377e5e971988a3add171c398eb654a866fab'
  - url: 'https://git.kernel.org/stable/c/cde5c7f0286c4203d0abc7248201542aa8bf33bb'
  - url: 'https://git.kernel.org/stable/c/03e9405c518c4d61f28079492f252d6d4e2bac5c'
  - url: 'https://git.kernel.org/stable/c/25fe708bbc59289d3d1ea4b126fbc1b460a072a5'
tags:
  - cve.org
epss: 0.00104
epssPercentile: 0.00962
ingestedAt: '2026-10-21T12:48:53.609Z'
---

## Overview

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

net: team: fix NULL pointer dereference in team_xmit during mode change

__team_change_mode() clears team->ops with memset() before restoring
safe dummy handlers via team_adjust_ops(). A concurrent team_xmit()
running under RCU on another CPU can read team->ops.transmit during
this window and call a NULL function pointer, crashing the kernel.

The race requires a mode change (CAP_NET_ADMIN) concurrent with
transmit on the team device.

 BUG: kernel NULL pointer dereference, address: 0000000000000000
 Oops: 0010 [#1] SMP KASAN NOPTI
 RIP: 0010:0x0
 Call Trace:
  team_xmit (drivers/net/team/team_core.c:1853)
  dev_hard_start_xmit (net/core/dev.c:3904)
  __dev_queue_xmit (net/core/dev.c:4871)
  packet_sendmsg (net/packet/af_packet.c:3109)
  __sys_sendto (net/socket.c:2265)

The original code assumed that no ports means no traffic, so mode
changes could freely memset()/memcpy() the ops.  AF_PACKET with
forced carrier breaks that assumption.

Prevent the race instead of making it safe: replace memset()/memcpy()
with per-field updates that never touch transmit or receive.  Those
two handlers are managed solely by team_adjust_ops(), which already
installs dummies when tx_en_port_count == 0 (always true during mode
change since no ports are present).  WRITE_ONCE/READ_ONCE prevent
store/load tearing on the handler pointers.

synchronize_net() before exit_op() drains in-flight readers that may
still reference old mode state from before port removal switched the
handlers to dummies.

## Affected

- `Linux >= 3d249d4ca7d0ed6629a135ea1ea21c72286c0d80 < 9486377e5e971988a3add171c398eb654a866fab`
- `Linux >= 3d249d4ca7d0ed6629a135ea1ea21c72286c0d80 < cde5c7f0286c4203d0abc7248201542aa8bf33bb`
- `Linux >= 3d249d4ca7d0ed6629a135ea1ea21c72286c0d80 < 03e9405c518c4d61f28079492f252d6d4e2bac5c`
- `Linux >= 3d249d4ca7d0ed6629a135ea1ea21c72286c0d80 < 25fe708bbc59289d3d1ea4b126fbc1b460a072a5`
- `Linux 3.3`

## Remediation

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