In the Linux kernel, the following vulnerability has been resolved: tcp: fix potential race in tcp_v6_syn_recv_sock() Code in tcp_v6_syn_recv_sock() after the call to tcp_v4_syn_recv_sock() is done too late. After tcp_v4_syn_recv_sock(), the child socket is already visible from TCP ehash table and other cpus might use it. Since newinet->pinet6 is still pointing to the listener ipv6_pinfo bad things can happen as syzbot found. Move the problematic code in tcp_v6_mapped_child_init() and call this new helper from tcp_v4_syn_recv_sock() before the ehash insertion. This allows the removal of one tcp_sync_mss(), since tcp_v4_syn_recv_sock() will call it with the correct context.

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).

Red Hat Enterprise Linux 10 Affected kernel Red Hat Enterprise Linux 6 Under investigation kernel Red Hat Enterprise Linux 7 Affected kernel Red Hat Enterprise Linux 7 Affected kernel-rt Red Hat Enterprise Linux 8 Affected kernel Red Hat Enterprise Linux 8 Affected kernel-rt Red Hat Enterprise Linux 9 Affected kernel Red Hat Enterprise Linux 9 Affected kernel-rt https://www.cve.org/CVERecord?id=CVE-2026-43198 https://nvd.nist.gov/vuln/detail/CVE-2026-43198 https://lore.kernel.org/linux-cve-announce/2026050645-CVE-2026-43198-0870@gregkh/T