---
id: CVE-2026-53069
title: 'net, bpf: fix null-ptr-deref in xdp_master_redirect() for down master'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  net, bpf: fix null-ptr-deref in xdp_master_redirect() for down master

  syzkaller reported a kernel panic in bond_rr_gen_slave_id() reached via
  xdp_master_redirect(). Fu…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cvssSource: cna
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 879af96ffd72706c6e3278ea6b45b0b0e37ec5d7 <
    3128b294b426533c8d9162187446d93a8a160359
  - >-
    Linux >= 879af96ffd72706c6e3278ea6b45b0b0e37ec5d7 <
    acbf45bd584d924b320bee2a7fe2a26f64904d95
  - >-
    Linux >= 879af96ffd72706c6e3278ea6b45b0b0e37ec5d7 <
    866d3d9b87751b1944168fd82615505e0c0fd6cf
  - >-
    Linux >= 879af96ffd72706c6e3278ea6b45b0b0e37ec5d7 <
    183128da0406b1c10e6f60b7b9fe70788b9c8c1d
  - >-
    Linux >= 879af96ffd72706c6e3278ea6b45b0b0e37ec5d7 <
    7bad93e99737e4a5c0c14ac50c05152cf4e28022
  - >-
    Linux >= 879af96ffd72706c6e3278ea6b45b0b0e37ec5d7 <
    ea690b3b6e58ae00979af8195b4cc24df466b65e
  - >-
    Linux >= 879af96ffd72706c6e3278ea6b45b0b0e37ec5d7 <
    1921f91298d1388a0bb9db8f83800c998b649cb3
  - Linux 5.15
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-10-16T15:25:03.791901Z'
published: '2026-06-24'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T15:31:30.133Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-53069'
references:
  - url: 'https://git.kernel.org/stable/c/3128b294b426533c8d9162187446d93a8a160359'
  - url: 'https://git.kernel.org/stable/c/acbf45bd584d924b320bee2a7fe2a26f64904d95'
  - url: 'https://git.kernel.org/stable/c/866d3d9b87751b1944168fd82615505e0c0fd6cf'
  - url: 'https://git.kernel.org/stable/c/183128da0406b1c10e6f60b7b9fe70788b9c8c1d'
  - url: 'https://git.kernel.org/stable/c/7bad93e99737e4a5c0c14ac50c05152cf4e28022'
  - url: 'https://git.kernel.org/stable/c/ea690b3b6e58ae00979af8195b4cc24df466b65e'
  - url: 'https://git.kernel.org/stable/c/1921f91298d1388a0bb9db8f83800c998b649cb3'
tags:
  - cve.org
epss: 0.0038
epssPercentile: 0.3039
ingestedAt: '2026-10-16T17:24:46.728Z'
---

## Overview

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

net, bpf: fix null-ptr-deref in xdp_master_redirect() for down master

syzkaller reported a kernel panic in bond_rr_gen_slave_id() reached via
xdp_master_redirect(). Full decoded trace:

  https://syzkaller.appspot.com/bug?extid=80e046b8da2820b6ba73

bond_rr_gen_slave_id() dereferences bond->rr_tx_counter, a per-CPU
counter that bonding only allocates in bond_open() when the mode is
round-robin. If the bond device was never brought up, rr_tx_counter
stays NULL.

The XDP redirect path can still reach that code on a bond that was
never opened: bpf_master_redirect_enabled_key is a global static key,
so as soon as any bond device has native XDP attached, the
XDP_TX -> xdp_master_redirect() interception is enabled for every
slave system-wide. The path xdp_master_redirect() ->
bond_xdp_get_xmit_slave() -> bond_xdp_xmit_roundrobin_slave_get() ->
bond_rr_gen_slave_id() then runs against a bond that has no
rr_tx_counter and crashes.

Fix this in the generic xdp_master_redirect() by refusing to call into
the master's ->ndo_xdp_get_xmit_slave() when the master device is not
up. IFF_UP is only set after ->ndo_open() has successfully returned,
so this reliably excludes masters whose XDP state has not been fully
initialized. Drop the frame with XDP_ABORTED so the exception is
visible via trace_xdp_exception() rather than silently falling through.
This is not specific to bonding: any current or future master that
defers XDP state allocation to ->ndo_open() is protected.

## Affected

- `Linux >= 879af96ffd72706c6e3278ea6b45b0b0e37ec5d7 < 3128b294b426533c8d9162187446d93a8a160359`
- `Linux >= 879af96ffd72706c6e3278ea6b45b0b0e37ec5d7 < acbf45bd584d924b320bee2a7fe2a26f64904d95`
- `Linux >= 879af96ffd72706c6e3278ea6b45b0b0e37ec5d7 < 866d3d9b87751b1944168fd82615505e0c0fd6cf`
- `Linux >= 879af96ffd72706c6e3278ea6b45b0b0e37ec5d7 < 183128da0406b1c10e6f60b7b9fe70788b9c8c1d`
- `Linux >= 879af96ffd72706c6e3278ea6b45b0b0e37ec5d7 < 7bad93e99737e4a5c0c14ac50c05152cf4e28022`
- `Linux >= 879af96ffd72706c6e3278ea6b45b0b0e37ec5d7 < ea690b3b6e58ae00979af8195b4cc24df466b65e`
- `Linux >= 879af96ffd72706c6e3278ea6b45b0b0e37ec5d7 < 1921f91298d1388a0bb9db8f83800c998b649cb3`
- `Linux 5.15`

## Remediation

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