JPEG 2000 is a still-image compression format and codec that was designed to improve on classic JPEG. It uses more complex structures and decoding logic than many simpler image formats, which gives it strong compression features but also a larger attack surface when software must parse it.
In cyber security, JPEG 2000 matters because attackers can hide malicious image data inside files that seem to be ordinary documents, especially PDFs and office files that embed images. If a parser or renderer has a memory-safety bug in its JPEG 2000 handling, a crafted file can trigger a crash, data corruption, or even remote code execution. Defenders reduce the risk by patching document engines, sandboxing conversion services, restricting untrusted uploads, and using least-privilege workers so one parsing flaw cannot compromise the whole system.