CVE-2026-63660

Name of the Vulnerable Software and Affected Versions node-fontnik versions prior to 0.7.7

Description A heap out-of-bounds write occurs when processing a specially crafted font. The issue resides in the RenderSDF() function (include/mapbox/glyph foundry impl.hpp), where the SDF (signed distance fields) bitmap allocation size is calculated as buffered width * buffered height using a 32-bit unsigned integer. Because glyph dimensions are derived from the font's outline bounding box without an upper bound, a sufficiently large glyph can cause the calculation to exceed 2³², resulting in an integer wrap-around to a small value. This leads to an under-allocated buffer, while the render loop continues to write one byte per pixel, causing heap corruption and process crashes.

Recommendations Update node-fontnik to version 0.7.7.