CVE-2026-43254

Technical Description

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

ovpn: tcp - fix packet extraction from stream

When processing TCP stream data in ovpn_tcp_recv, we receive large

cloned skbs from __strp_rcv that may contain multiple coalesced packets.

The current implementation has two bugs:

1. Header offset overflow: Using pskb_pull with large offsets on

coalesced skbs causes skb->data - skb->head to exceed the u16 storage

of skb->network_header. This causes skb_reset_network_header to fail

on the inner decapsulated packet, resulting in packet drops.

2. Unaligned protocol headers: Extracting packets from arbitrary

positions within the coalesced TCP stream provides no alignment

guarantees for the packet data causing performance penalties on

architectures without efficient unaligned access. Additionally,

openvpn's 2-byte length prefix on TCP packets causes the subsequent

4-byte opcode and packet ID fields to be inherently misaligned.

Fix both issues by all

Remediation

Check the references section for vendor advisories and patches from linux. Update linux_kernel to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

Affected Products

References