When does an expressive format become an attack surface?
A format can admit computation its designer did not anticipate. That changes what it means to process input supplied by someone else.
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Can presentation slides perform general computation? →Compare a deliberately minimal interpreter with a surprising construction inside slides. The decisive question is which operations the system can express.Where should untrusted input stop? →Compare an instruction embedded in model input with data entering a parser. Both examples ask who gets to decide what is treated as an instruction.Should a parser repair invalid input? →Correcting an input can make a system convenient, but another component may interpret the correction differently. Rejection makes that boundary explicit.
Compare the passages
essentially imitate any transition function of any other touring machinetreat input handling computational power as privilege and reduce that privilege