Fragnesia (CVE-2026-46300): Linux Kernel LPE via XFRM ESP-in-TCP

Local privilege escalation in Linux kernel XFRM ESP-in-TCP subsystem (Fragnesia vulnerability) allows authenticated local attackers to overwrite kernel memory structures by exploiting arbitrary byte writes into the kernel page cache of read-only files. CVSS score of 7.8 reflects high impact across confidentiality, integrity, and availability. Low attack complexity (AC:L) and no user interaction requirement (UI:N) make this exploitable by any local user with basic privileges. No confirmed active exploitation (not in CISA KEV) or public proof-of-concept identified at time of analysis, but the specific vulnerability name 'Fragnesia' suggests coordinated disclosure with security research community.