CVE-2026-68121

HighCVSS 7.8/10Last modified Oct 19, 2026

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.

Metrics

CVSS 3.1 7.8/10CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Weakness enumeration

CWE-416

Affected software

Source: the vendor's advisory (CNA). NVD analysis pending.

No affected versions have been published.

Timeline

Published
Aug 10, 2026
Last modified
Oct 19, 2026
NVD status
Received

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CVE-2026-68121: High severity, CVSS 7.8 | Vulnix