Core Linux kernel TCP path; high severity (9.8) and widespread Linux deployments; potential escalation/DoS risk.
CVE-2026-43198
Linux kernel TCPv6 race in tcp_v6_syn_recv_sock() may enable timing-based misuse.
Is CVE-2026-43198 being exploited?
Not confirmed. CVE-2026-43198 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.30% probability of exploitation in the next 30 days.
How severe is CVE-2026-43198?
CVE-2026-43198 is rated Critical with a CVSS score of 9.8. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-43198?
Yes. A fix has been recorded for CVE-2026-43198. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-43198 affect?
CVE-2026-43198 affects Linux kernel. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-43198?
Patch to fixed kernel version and reboot.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Race could lead to kernel instability or local privilege escalation via mis-timed socket initialization.
Immediate action required
- affected>= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and < fe89b2f05b854847784f91127319172945c1fadd
- affected>= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and < 7178e2a8027423b2af17ab95df73a749a5b72e5b
- affected>= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and < 858d2a4f67ff69e645a43487ef7ea7f28f06deae
- affected2.6.12
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.