Fixed kernels for a use-after-free vulnerability in the Linux kernel's IPv4 TCP code are now available for Red Hat Enterprise Linux 8, 9, and 10, while Ubuntu's fixes for its three newest long-term-support releases remain in its opt-in testing channel with no date for a regular update. The flaw, tracked as CVE-2026-98432, can be reached by a remote, unauthenticated attacker and can lead to remote code execution, Red Hat and Canonical said. The Linux kernel's own CVE team rates the flaw 9.8 out of 10 on the CVSS scale. Red Hat, which initially rated it Moderate at 5.9, has raised its score to 9.8 and now calls it Critical. The bug has been present since Linux 4.4, and the upstream fix landed in October. What the Flaw Is When a server accepts an IPv4 TCP connection, the kernel passes IP…