Definition
Plain language
A trusted helper that uses its own authority to do something on behalf of someone who was never allowed to ask for it.
As stated in the literature
A classic access-control failure in which an intermediary with legitimate permissions acts on a request whose true origin lacks those permissions, because authority is inferred from position rather than carried with the request.
Also called: confused-deputy
Why it matters: It explains why giving an AI agent broad permissions is dangerous even when the agent itself is honest — the agent's authority can be borrowed by whoever manages to make a request.
For example, a mail-sorting clerk with a master key opens a locked cabinet because a note slipped under the door asked him to, even though whoever wrote the note had no right to that cabinet.
Heard on the show
“There’s an older security term for this shape: a confused deputy.”Episode 250 — The Same Model Refused a Backdoor, Then Its Own Sub-Agent Ran It