CVE-2026-43198

high

Description

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.

References

https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-43198.json

https://git.kernel.org/stable/c/fe89b2f05b854847784f91127319172945c1fadd

https://git.kernel.org/stable/c/858d2a4f67ff69e645a43487ef7ea7f28f06deae

https://git.kernel.org/stable/c/7178e2a8027423b2af17ab95df73a749a5b72e5b

https://bugzilla.redhat.com/show_bug.cgi?id=2467228

https://access.redhat.com/security/cve/CVE-2026-43198

https://access.redhat.com/errata/RHSA-2026:34443

https://access.redhat.com/errata/RHSA-2026:34094

https://access.redhat.com/errata/RHSA-2026:33285

https://access.redhat.com/errata/RHSA-2026:33215

https://access.redhat.com/errata/RHSA-2026:30129

Details

Source: Mitre, NVD

Published: 2026-05-06

Updated: 2026-07-02

Risk Information

CVSS v2

Base Score: 10

Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C

Severity: Critical

CVSS v3

Base Score: 7

Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

Severity: High

EPSS

EPSS: 0.00017