The OpenType Sanitizer (OTS) parses and serializes OpenType files (OTF, TTF) and WOFF and WOFF2 font files, validating them and sanitizing them as it goes.
The C library is integrated into Chromium and Firefox, and also simple command line tools to check files offline in a Terminal.
The CSS font-face property is great for web typography. Having to use images in order to get the correct typeface is a great sadness; one should be able to use vectors.
However, on many platforms the system-level TrueType font renderers have never been part of the attack surface before, and putting them on the front line is a scary proposition... Especially on platforms like Windows, where it's a closed-source blob running with high privilege.
Thanks to Alex Russell for the original idea.