CVE-2026-68121

pppoe: reload header pointer after dev_hard_header()

State: Published
Severity: 7.8 High
Published: Aug 10, 2026
Updated: Oct 19, 2026
Reserved: Jul 30, 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.

Scores

CVSS	Score	Vector	Source
3.1	7.8 High	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H	Linux

Weaknesses

CWE-416 Use After Free

Affected Products

Product	Versions
LinuxLinux	1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 7a56e7c9b08e08fd55a1bcada24cf4fe3782b722Affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 6eed5ae7887a93160803d2b81ff88e75eefd4a4cAffected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before ba3409369c5413cdf0dcbf3a928f76b48e8c3e6aAffected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before e6493a4d1ee17595766165fa446d45b7e0c318d0Affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 7e9fbd7f96bcde63a7c798fe16b38cedee7a1501Affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 6866abf59976d273164a6624234d96a967280223Affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before bed4caecd723693f750e13adbb2c42ca1249a3fdAffected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before e9c238f6fe42fb1b4dba3a578277de32cb487937Affected
LinuxLinux	2.6.12Affected before 2.6.12Not affected 5.10.265 through 5.10.Not affected 5.15.216 through 5.15.Not affected 6.1.183 through 6.1.Not affected 6.6.148 through 6.6.Not affected 6.12.101 through 6.12.Not affected 6.18.42 through 6.18.Not affected 7.1.6 through 7.1.*Not affected 7.2 and laterNot affected

Product

Versions

LinuxLinux

1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 7a56e7c9b08e08fd55a1bcada24cf4fe3782b722Affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 6eed5ae7887a93160803d2b81ff88e75eefd4a4cAffected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before ba3409369c5413cdf0dcbf3a928f76b48e8c3e6aAffected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before e6493a4d1ee17595766165fa446d45b7e0c318d0Affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 7e9fbd7f96bcde63a7c798fe16b38cedee7a1501Affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 6866abf59976d273164a6624234d96a967280223Affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before bed4caecd723693f750e13adbb2c42ca1249a3fdAffected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before e9c238f6fe42fb1b4dba3a578277de32cb487937Affected

LinuxLinux

2.6.12Affected
before 2.6.12Not affected
5.10.265 through 5.10.*Not affected
5.15.216 through 5.15.*Not affected
6.1.183 through 6.1.*Not affected
6.6.148 through 6.6.*Not affected
6.12.101 through 6.12.*Not affected
6.18.42 through 6.18.*Not affected
7.1.6 through 7.1.*Not affected
7.2 and laterNot affected

References

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