Red Hat Patches 9.8-Rated Linux TCP RCE Flaw While Ubuntu Releases Fixes for Testing
Summary: Red Hat shipped fixed kernels for RHEL 8, 9, and 10 on November 1 for CVE-2026-98432, a use-after-free in the Linux kernel's IPv4 TCP code that a remote, unauthenticated attacker can reach to achieve remote code execution, rated 9.8 by the kernel CVE team. Canonical said on November 2 that fixes for Ubuntu 22.04, 24.04, and 26.04 LTS sit in its opt-in -proposed testing channel with no release date, while Ubuntu 20.04, 18.04, and 16.04 have no fix yet.
What's compelling: The bug has existed since Linux 4.4 and needs no login, only a connection request carrying IPv4 Record Route or Timestamp options to any listening TCP port, and Anthropic reported an unreleased internal Claude model wrote a working remote root exploit for it in 48 minutes to leak a kernel address plus 5 more to reach a root shell.