Vulnerability in Linux

CVE-2026-43198

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.

Vulnerability class: Race Condition

Published · last modified .

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.003 (21.3th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 21st percentile — 21.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-43198: held from 0.003 to 0.003.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000

Affected products

  • Linux — versions 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, 2.6.12, 0
  • Linux Kernel — versions 2.6.12, 7.0

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-43198?
CVE-2026-43198 is a critical-severity vulnerability in Linux, classified under Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition). CVSS score: 9.8/10. Published 2026-05-06.
How severe is CVE-2026-43198?
Critical severity. CVSS v3 base score is 9.8 out of 10.