---
id: CVE-2026-68121
title: 'pppoe: reload header pointer after dev_hard_header()'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  pppoe: reload header pointer after dev_hard_header()

  pppoe_sendmsg() saves a pointer to the PPPoE header before calling
  dev_hard_header(). Device header callbacks are …
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cvssSource: cna
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    7a56e7c9b08e08fd55a1bcada24cf4fe3782b722
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    6eed5ae7887a93160803d2b81ff88e75eefd4a4c
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    ba3409369c5413cdf0dcbf3a928f76b48e8c3e6a
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    e6493a4d1ee17595766165fa446d45b7e0c318d0
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    7e9fbd7f96bcde63a7c798fe16b38cedee7a1501
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    6866abf59976d273164a6624234d96a967280223
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    bed4caecd723693f750e13adbb2c42ca1249a3fd
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    e9c238f6fe42fb1b4dba3a578277de32cb487937
  - Linux 2.6.12
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-16T15:44:11.187043Z'
exploitAvailable: true
published: '2026-08-10'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T15:52:57.830Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-68121'
references:
  - url: 'https://git.kernel.org/stable/c/7a56e7c9b08e08fd55a1bcada24cf4fe3782b722'
  - url: 'https://git.kernel.org/stable/c/6eed5ae7887a93160803d2b81ff88e75eefd4a4c'
  - url: 'https://git.kernel.org/stable/c/ba3409369c5413cdf0dcbf3a928f76b48e8c3e6a'
  - url: 'https://git.kernel.org/stable/c/e6493a4d1ee17595766165fa446d45b7e0c318d0'
  - url: 'https://git.kernel.org/stable/c/7e9fbd7f96bcde63a7c798fe16b38cedee7a1501'
  - url: 'https://git.kernel.org/stable/c/6866abf59976d273164a6624234d96a967280223'
  - url: 'https://git.kernel.org/stable/c/bed4caecd723693f750e13adbb2c42ca1249a3fd'
  - url: 'https://git.kernel.org/stable/c/e9c238f6fe42fb1b4dba3a578277de32cb487937'
tags:
  - cve.org
  - exploit-available
epss: 0.00298
epssPercentile: 0.20983
exploits:
  github: 3
  githubRepos:
    - 'https://github.com/suominen/pppoeject'
    - 'https://github.com/0xBlackash/CVE-2026-68121'
    - 'https://github.com/HORKimhab/CVE-2026-68121'
  checkedAt: '2026-10-16T17:25:21.016Z'
ingestedAt: '2026-10-16T17:24:46.840Z'
---

## Overview

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

pppoe: reload header pointer after dev_hard_header()

pppoe_sendmsg() saves a pointer to the PPPoE header before calling
dev_hard_header(). Device header callbacks are allowed to reallocate the
skb head, invalidating pointers into it.

This can happen when a send is blocked in copy_from_user() while the first
non-Ethernet port is added to an empty team device. The team's delegated
GRE header callback then expands the skb head. PPPoE subsequently writes
six bytes through the stale pointer into the freed head.

Reload the PPPoE header through the skb's network-header offset after
device header creation. pskb_expand_head() updates that offset when it
relocates the head.

## Affected

- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 7a56e7c9b08e08fd55a1bcada24cf4fe3782b722`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 6eed5ae7887a93160803d2b81ff88e75eefd4a4c`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < ba3409369c5413cdf0dcbf3a928f76b48e8c3e6a`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < e6493a4d1ee17595766165fa446d45b7e0c318d0`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 7e9fbd7f96bcde63a7c798fe16b38cedee7a1501`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 6866abf59976d273164a6624234d96a967280223`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < bed4caecd723693f750e13adbb2c42ca1249a3fd`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < e9c238f6fe42fb1b4dba3a578277de32cb487937`
- `Linux 2.6.12`

## Remediation

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