CVE-2026-31635 (DirtyDecrypt) Linux Kernel Privilege Escalation Explained

**Executive Summary:** CVE-2026-31635 (DirtyDecrypt / DirtyCBC) is a Linux kernel local privilege-escalation vulnerability in the AF_RXRPC RxGK security layer that lets a local attacker, who supplies the encryption key and crafts spliced packets, cause in-place CBC decryption to overwrite page-cache contents of a readable SUID-root binary and then execute it to gain root; the report details the root cause, the five-step exploitation sequence, affected kernel components, and simulation guidance via the Picus Platform.