Race / parallel-action probes
Two sessions you own, one unique action, one RTT. Measure leftover extra credit, not a drained victim.
Tags: race, toctou, limit
Controlled probes
N parallel POST /redeem with the same couponIdempotency-Key: A on two different bodiesparallel enable-mfa and disable-mfa from two cookies you own
Source: https://portswigger.net/research/smashing-the-state-machine