---
id: CVE-2026-99066
title: 'can: dev: init_can_skb(): restore skb header initialization'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  can: dev: init_can_skb(): restore skb header initialization

  Commit 9f10374bb024 ("can: remove private CAN skb headroom infrastructure")
  removed the skb_reset_mac_heade…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 9f10374bb024593a611e6845847f0444841a231b <
    8078375dfd0baecd9f1b7b06bb2d6f88d7cb8632
  - >-
    Linux >= 9f10374bb024593a611e6845847f0444841a231b <
    0a04c0cb8606ff88399489d03ef255afe90d0d5f
  - Linux 7.0
published: '2026-10-23'
updated: '2026-10-23'
sourceUpdated: '2026-10-23T12:23:09.516Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-99066'
references:
  - url: 'https://git.kernel.org/stable/c/8078375dfd0baecd9f1b7b06bb2d6f88d7cb8632'
  - url: 'https://git.kernel.org/stable/c/0a04c0cb8606ff88399489d03ef255afe90d0d5f'
tags:
  - cve.org
ingestedAt: '2026-10-23T13:24:55.520Z'
---

## Overview

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

can: dev: init_can_skb(): restore skb header initialization

Commit 9f10374bb024 ("can: remove private CAN skb headroom infrastructure")
removed the skb_reset_mac_header()/skb_reset_network_header()/
skb_reset_transport_header() calls from init_can_skb(). As a result, RX
skbs from alloc_can_skb() and friends again carry mac_header = 0xFFFF.
When such an skb reaches packet_rcv_spkt() (SOCK_PACKET), the push length
calculation overflows and triggers skb_under_panic -> kernel BUG -> full
machine panic.

The same issue was originally reported in 2014 on linux-can and fixed by
commit 969439016d2c ("can: add missing initialisations in CAN related
skbuffs"). packet_rcv_spkt() itself has never been hardened: only
packet_rcv() and tpacket_rcv() gained dev_has_header() checks in
commit d549699048b4 ("net/packet: fix packet receive on L3 devices
without visible hard header").

## Affected

- `Linux >= 9f10374bb024593a611e6845847f0444841a231b < 8078375dfd0baecd9f1b7b06bb2d6f88d7cb8632`
- `Linux >= 9f10374bb024593a611e6845847f0444841a231b < 0a04c0cb8606ff88399489d03ef255afe90d0d5f`
- `Linux 7.0`

## Remediation

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