CVE-2026-43198: In the Linux kernel, the following vulnerability has been resolved: tcp: fix potential race in tcp_v6_syn_rec

Q: How do I fix CVE-2026-43198?

linux kernel: upgrade to 6.18.16, 6.19.6. Exact commands for each OS are on this page.

Q: Is CVE-2026-43198 being exploited?

CVE-2026-43198 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-43198 affect?

CVE-2026-43198 affects linux kernel. Severity is critical (CVSS 9.8). 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(),

Q: How urgent is CVE-2026-43198?

Priority 50/100. Critical severity; Remotely exploitable, no login, no user action; On your watchlist

This month

CRITICAL 9.8REMOTEWATCHLISTUPGRADE

CVE-2026-43198 is a critical-severity flaw (CVSS 9.8) affecting linux kernel. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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 proble

Why this priority

Critical severity
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.3% (top 78%)
CISA exploited list	No
Weakness	CWE-362, CWE-821
Published	2026-05-06
Last modified	2026-10-19

Publisher (CNA): kernel.org · Vendor: linux

Last updated 2026-10-19 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-05-06 12:16 UTCPublished CVE record published
2026-10-19 20:18 UTCUpdated Record last modified

linux linux kernel UPGRADE

Affected: >= 2.6.12.1 and < 6.18.16 · >= 6.19 and < 6.19.6 · 2.6.12 · 2.6.12 rc2 · 2.6.12 rc3 · 2.6.12 rc4 · 2.6.12 rc5 · 7.0 rc1

Fixed in: 6.18.16, 6.19.6

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Advisories and coverage

Official advisories

AlmaLinux Errata: [ALSA-2026:33285] Important: kernel security, bug fix, and enhancement update 2026-07-01

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-43198?

linux kernel: upgrade to 6.18.16, 6.19.6. Exact commands for each OS are on this page.

Is CVE-2026-43198 being exploited?

CVE-2026-43198 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-43198 affect?

CVE-2026-43198 affects linux kernel. Severity is critical (CVSS 9.8). 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(),

How urgent is CVE-2026-43198?

Priority 50/100. Critical severity; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Linux kernel vulnerabilities

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References

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