IT

Tracker / CVE-2026-31684

CVE-2026-31684

Medium 5.5

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.

Affected products and versions

linux linux_kernel
linux linux_kernel · 4.19.99 → 4.20
linux linux_kernel · 5.1 → 6.6.136
linux linux_kernel · 6.13 → 6.18.24
linux linux_kernel · 6.19 → 6.19.14
linux linux_kernel · 6.7 → 6.12.83

Analysis

This page is not indexable yet.Until it carries original analysis — what it actually exposes, how to check in two minutes whether a system was touched, what to do if it was — the page stays noindex. The database decides that, not the template.

References