Definition
Plain language
A ubiquitous command-line tool and library for transferring data over the internet.
As stated in the literature
A widely deployed open-source library and CLI for HTTP and other network transfers; appears as a target codebase in automated vulnerability-discovery work, where its multi-step session setup (init, then repeated setopt, then callbacks) made it resistant to short-horizon agentic analysis.
Why it matters: Because it is built into countless systems and scripts, a flaw in it could ripple across a huge amount of software, and its multi-step usage also makes it a tough test for automated bug-hunting agents.
For example, a developer might use curl in one line to download a file or send data to a web service from the terminal.