Abandonware is software that is no longer maintained or supported by its original developer. It may still run, still be installed, and still handle important tasks, but it no longer receives security patches, compatibility updates, or vendor oversight.
In cyber security, abandonware matters because old code often becomes a permanent attack surface. Unpatched libraries, stale endpoints, weak transport settings, and forgotten authentication logic can remain active long after the product is sold or discontinued. Attackers look for these gaps to intercept traffic, abuse outdated dependencies, or exploit known flaws that will never be fixed. Defenders treat abandonware as a lifecycle risk: they inventory it, monitor its network behavior, restrict exposure, and plan retirement or replacement before support ends. In connected environments, especially IoT companion apps and legacy business tools, unsupported software can keep mediating trust even after the vendor has moved on.