Linux Kernel 'Copy Fail' Vulnerability Poses High Risk for System Takeover
A high-severity logic flaw in the Linux kernel, identified as CVE-2026-31431 and dubbed 'Copy Fail,' has been reported by cybersecurity firm Theori. This vulnerability allows unprivileged attackers to write code to other files' memory, potentially gaining root shell access. The flaw affects all Linux distributions since 2017 and is linked to the kernel's authencesn Authenticated Encryption with Associated Data (AEAD) template, used by IPsec for Extended Sequence Number (ESN) support. The issue arises from a 2017 optimization that placed page cache pages in a writable scatterlist, allowing attackers to modify the in-memory copy of any setuid-root binary readable by the user. 
