An embedded font is a font file packaged inside a document, such as a PDF or office file, so the text can render exactly as the author intended even if the viewer does not have that font installed. This improves portability and visual fidelity, but it also adds another binary object that the document parser must inspect.
In cyber security, embedded fonts matter because they are parsed automatically by readers, previewers, and operating-system rendering stacks. Attackers can abuse that trust boundary by crafting malformed font data to trigger memory-safety bugs such as out-of-bounds writes, crashes, or, in some cases, more serious code execution paths. Defenders reduce risk with patching, sandboxing, hardened parsers, and caution around unsolicited documents, especially when a file contains nested content that is processed before the user sees it.