CVE-2026-31684

net: sched: act_csum: validate nested VLAN headers

State: Published
Severity: Not scored
Published: Apr 25, 2026
Updated: Jun 1, 2026
Reserved: Mar 9, 2026

Description

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

net: sched: act_csum: validate nested VLAN headers

tcf_csum_act() walks nested VLAN headers directly from skb->data when an skb still carries in-payload VLAN tags. The current code reads vlan->h_vlan_encapsulated_proto and then pulls VLAN_HLEN bytes without first ensuring that the full VLAN header is present in the linear area.

If only part of an inner VLAN header is linearized, accessing h_vlan_encapsulated_proto reads past the linear area, and the following skb_pull(VLAN_HLEN) may violate skb invariants.

Fix this by requiring pskb_may_pull(skb, VLAN_HLEN) before accessing and pulling each nested VLAN header. If the header still is not fully available, drop the packet through the existing error path.

Scores

The record has no CVSS score.

Weaknesses

The record names no weakness.

Affected Products

Product	Versions
LinuxLinux	2ecba2d1e45b24620a7c3df9531895cf68d5dec6 to before 0410c619e86551677fb79887a38eccad3f5a0725Affected 2ecba2d1e45b24620a7c3df9531895cf68d5dec6 to before 886469b6455611a511aa6013e957e15e50577513Affected 2ecba2d1e45b24620a7c3df9531895cf68d5dec6 to before 46c07ad50fa2f4ba7663ee1b72b75ad7ad45cf09Affected 2ecba2d1e45b24620a7c3df9531895cf68d5dec6 to before eb3765b90eb8f2a3d6310a80c14a9e57ec4267a2Affected 2ecba2d1e45b24620a7c3df9531895cf68d5dec6 to before a69738efea0996d05a3c7d2178551b891744df1bAffected 2ecba2d1e45b24620a7c3df9531895cf68d5dec6 to before ec4930979b3f7bbeb7af5744599fc6603a4dba62Affected 2ecba2d1e45b24620a7c3df9531895cf68d5dec6 to before 3d165d975305cf76ff0b10a3c798fb31e5f5f9a5Affected 2ecba2d1e45b24620a7c3df9531895cf68d5dec6 to before c842743d073bdd683606cb414eb0ca84465dd834Affected 3764bfae5056e95617b6ee074129297e11710886Affected 4.19.99 to before 4.20Affected
LinuxLinux	5.1Affected before 5.1Not affected 5.10.258 through 5.10.Not affected 5.15.209 through 5.15.Not affected 6.1.175 through 6.1.Not affected 6.6.136 through 6.6.Not affected 6.12.83 through 6.12.Not affected 6.18.24 through 6.18.Not affected 6.19.14 through 6.19.*Not affected 7.0 and laterNot affected

Product

Versions

LinuxLinux

2ecba2d1e45b24620a7c3df9531895cf68d5dec6 to before 0410c619e86551677fb79887a38eccad3f5a0725Affected
2ecba2d1e45b24620a7c3df9531895cf68d5dec6 to before 886469b6455611a511aa6013e957e15e50577513Affected
2ecba2d1e45b24620a7c3df9531895cf68d5dec6 to before 46c07ad50fa2f4ba7663ee1b72b75ad7ad45cf09Affected
2ecba2d1e45b24620a7c3df9531895cf68d5dec6 to before eb3765b90eb8f2a3d6310a80c14a9e57ec4267a2Affected
2ecba2d1e45b24620a7c3df9531895cf68d5dec6 to before a69738efea0996d05a3c7d2178551b891744df1bAffected
2ecba2d1e45b24620a7c3df9531895cf68d5dec6 to before ec4930979b3f7bbeb7af5744599fc6603a4dba62Affected
2ecba2d1e45b24620a7c3df9531895cf68d5dec6 to before 3d165d975305cf76ff0b10a3c798fb31e5f5f9a5Affected
2ecba2d1e45b24620a7c3df9531895cf68d5dec6 to before c842743d073bdd683606cb414eb0ca84465dd834Affected
3764bfae5056e95617b6ee074129297e11710886Affected
4.19.99 to before 4.20Affected

LinuxLinux

5.1Affected
before 5.1Not affected
5.10.258 through 5.10.*Not affected
5.15.209 through 5.15.*Not affected
6.1.175 through 6.1.*Not affected
6.6.136 through 6.6.*Not affected
6.12.83 through 6.12.*Not affected
6.18.24 through 6.18.*Not affected
6.19.14 through 6.19.*Not affected
7.0 and laterNot affected

References

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