CVE-2026-43198

A flaw was found in the Linux kernel. A race condition exists in the TCP (Transmission Control Protocol) IPv6 (Internet Protocol version 6) socket handling, specifically within the tcp_v6_syn_recv_sock() function. This occurs because a child socket becomes visible in the TCP hash table before its IPv6-specific information is fully initialized. A remote attacker could potentially exploit this timing window, leading to an unstable system state or unexpected behavior, which may result in a denial of service (DoS).

This vulnerability is rated as Important severity because winning the timing window during socket setup allows an attacker to corrupt kernel memory or trigger a system crash across multi-core systems, potentially leading to privilege escalation or complete denial of service. Standard Red Hat Enterprise Linux installations enable dual-stack TCP networking by default, exposing system daemons listening on IPv6 addresses to this concurrency flaw during rapid inbound connection handshakes. While triggering the synchronization failure requires precisely timed concurrent operations on newly established sockets, the potential blast radius affects host stability without requiring elevated administrative privileges.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.