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VulnerabilityPublished Updated

CVE-2026-68121: Linux kernel · pppoe: reload header pointer after dev_hard_header()

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 7.8 High · fixed in e6493a4d1ee17595766165fa446d45b7e0c318d0 : patch Linux kernel soon.

Data as of 26 Oct 2026, 13:07 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.3% chance of exploitation in 30 days – higher than 30% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CISA SSVC
Exploitation
No evidence of active exploitation and no public proof of concept
Automatable
Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact
Total control over the software or total information disclosure

CISA SSVC assessment, 2026-10-16.

Patch
Available – fixed in e6493a4d1ee17595766165fa446d45b7e0c318d0, e9c238f6fe42fb1b4dba3a578277de32cb487937, bed4caecd723693f750e13adbb2c42ca1249a3fd +5
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 10 Aug 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < e6493a4d1ee17595766165fa446d45b7e0c318d0
Fixed in
  • e6493a4d1ee17595766165fa446d45b7e0c318d0
LinuxLinuxAffected
  • ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < e9c238f6fe42fb1b4dba3a578277de32cb487937
Fixed in
  • e9c238f6fe42fb1b4dba3a578277de32cb487937
LinuxLinuxAffected
  • ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < bed4caecd723693f750e13adbb2c42ca1249a3fd
Fixed in
  • bed4caecd723693f750e13adbb2c42ca1249a3fd
LinuxLinuxAffected
  • ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < ba3409369c5413cdf0dcbf3a928f76b48e8c3e6a
Fixed in
  • ba3409369c5413cdf0dcbf3a928f76b48e8c3e6a
LinuxLinuxAffected
  • ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 6866abf59976d273164a6624234d96a967280223
Fixed in
  • 6866abf59976d273164a6624234d96a967280223
LinuxLinuxAffected
  • ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 7e9fbd7f96bcde63a7c798fe16b38cedee7a1501
Fixed in
  • 7e9fbd7f96bcde63a7c798fe16b38cedee7a1501

Description

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.

References

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