Libcurl is the reusable client library behind curl. Developers embed it in applications to transfer data over protocols such as HTTP, HTTPS, FTP, and more, without writing network code from scratch. It provides common features like TLS handling, redirects, authentication, proxy support, and request management.
In cyber security, libcurl matters because a flaw in the library can affect many products at once, not just the curl command-line tool. Attackers may target applications that rely on libcurl to reach remote services, especially where input handling, redirects, certificates, or proxy settings are involved. Defenders should inventory where libcurl is used, verify patched versions or vendor backports, and rebuild or redeploy affected software so the fix reaches every embedded dependency.