New TONTOU CPU attack bypasses Spectre v2 fixes, leaks Linux password hashes

**TONTOU (Time-of-Neutralization to Time-of-Use) bypass of Spectre v2 mitigations enables kernel memory disclosure** — Researchers from MIT disclosed an interrupt-injection technique that re-poisons branch predictors after neutralization, allowing unprivileged code to leak kernel secrets (demonstrated on AMD Zen 2 with extraction of /etc/shadow at ~5.47 bytes/s); the attack is a sophisticated proof-of-concept requiring precise interrupt timing and control over unprivileged execution and is reported to be possible on Intel with additional complexity.