Monitor vulnerabilities like this one. Sign up free to get alerted when software you use is affected.
9.8

CVE-2026-43198: Linux Kernel: IPv6 Connection Race in TCP Protocol

CVE-2026-43198
Summary

A bug in the Linux kernel's TCP protocol for IPv6 connections has been fixed. This bug could have allowed other computers to use a new connection before it was fully set up, potentially causing errors. The fix is included in the latest Linux kernel updates, so it's recommended to update your system to ensure the fix is applied.

What to do

No fix is available yet. Check with your software vendor for updates.

Affected software
VendorProductAffected versions
linux linux_kernel >= 2.6.12.1, < 6.18.16
>= 6.19, < 6.19.6
2.6.12
7.0
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Original title
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 do...
Original 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.
nvd CVSS3.1 9.8
Vulnerability type
CWE-362 Race Condition
Published: 6 May 2026 · Updated: 28 May 2026 · First seen: 8 May 2026