CVE-2026-18497: The nothings stb TrueType library contains a heap buffer overflow vulnerability

A heap-buffer-overflow vulnerability exists in the nothings stb TrueType library, up to version 1.26, that is used for parsing TrueType font files. The vulnerability exists in the stbttGetGlyphShapeTT() function within the nothings stbtruetype.h library when parsing malformed TTF (TrueType Font) files. The vulnerability resides in the glyph data parsing path. An attacker can craft a malformed TTF file with an inflated endPtsOfContours value and truncate the remaining glyph data. When an application utilizing stbtruetype.h (such as various game engines or graphics software) attempts to load, bake, or render this malformed font via stbttGetGlyphShape(), the parser will attempt to read past the end of the glyph data buffer, triggering the out-of-bounds read.