Fragnesia (CVE-2026-46300): Frequently asked questions about new Linux Kernel XFRM ESP-in-TCP privilege escalation

Tenable's RSO published an FAQ on Fragnesia (CVE-2026-46300), a high-severity Linux kernel local privilege escalation in the XFRM ESP-in-TCP subsystem that permits local users to gain root via page-cache modification; a public PoC and a patch (May 13) exist, the exploit was confirmed on Ubuntu but not observed in the wild, and mitigations include a kernel update or blacklisting affected modules.