TONTOU Exploits a Timing Gap in Spectre Mitigations
MIT CSAIL researchers Daniel Trujillo and Mengjia Yan argue that processor defenses against Spectre can fail in the brief interval after a bad prediction is neutralized but before it is fully prevented from influencing execution. Their TONTOU attack uses carefully timed interrupts and cache delays to reopen that path, allowing a new speculative misprediction that can expose protected data. In a demonstration on affected AMD Zen processors, the team leaked password-hash data from the protected `/etc/shadow` file.
Eduardo Vela · Mengjia Yan · Daniël Trujillo·Aug 19, 2026·4 min read
