Linux TCP bug CVE-2026-98432: Red Hat has fixes now, Ubuntu still doesn't. How to check your servers
A CVSS 9.8 use-after-free in the kernel's IPv4 TCP handshake code affects kernels back to 4.4, and Anthropic says one of its models wrote a remote-root exploit for it. Red Hat shipped kernels on November 1; Ubuntu users are still waiting. Here's the status by distro and what to do in the meantime.