What is a patch?
A patch is a software update targeted to fix one or more vulnerabilities. Good software developers are constantly testing their code and issuing new patches to users. See also vulnerability.
How does a patch work?
A security patch is issued to close an exploit that can be taken advantage of to cause an unintended behavior in the software. Other types of patches fix bugs and add improvements. Most patches come from the original developer, but some are created by third parties.
Patches are often denoted by a software application’s version. For example, version 1.0 is the first complete version of a video game, but version 1.02 adds a patch to fix bugs and security holes. Patches can usually be downloaded and installed on top of an existing application, as opposed re-installing the entire application.