CVE-2026-43254

High

Published: 06/05/2026(UTC)Translated: 15/06/2026(UTC)NVD NIST

Summary

A vulnerability has been identified in the Linux kernel related to the ovpn module, concerning the processing of TCP stream data. Issues with header offset overflow and misaligned protocol headers may lead to packet loss and performance degradation.

Risk Assessment

Organizations may experience connection reliability issues and reduced performance in applications using OpenVPN, potentially impacting the security and availability of services.

Recommendation

It is recommended to update the Linux kernel to the latest version to mitigate this vulnerability and improve packet handling in the ovpn module.

Other vulnerabilities in Linux kernel - ovpn module

CVE-2026-45929High
A vulnerability in the Linux kernel has been fixed in the ovpn module, which could lead to a use-after-free condition in the ovpn_net_xmit function. The issue stemmed from improper pointer management during operations on packet segments.

Original NVD description (English source)

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