New Spectre-v2 BTR Attack Leaks Linux Memory Despite Existing Defenses

Researchers at VUSec and Scuola Superiore Sant'Anna have discovered a new Spectre v2 variant, BTR, that exploits stale branch prediction entries in JIT engines across multiple CPU vendors, including Linux kernels and GraalVM. The discovery highlights a fundamental flaw in how modern CPUs handle self-modifying/JITted code, leaving a potential avenue for future vulnerabilities.