Answer in brief
CVE-2026-63660 records a High severity (CVSS 8.1) vulnerability in node-fontnik: integer-overflow heap out-of-bounds write in RenderSDF. The current sources do not mark it as known exploited. The current feed maps mapbox/node-fontnik (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 8.1. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps mapbox/node-fontnik (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| mapbox/node-fontnikgeneric | <0.7.7 | 0.7.7 |
Published upstream
Nov 11, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Nov 11, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Nov 11, 2026
node-fontnik is a library that delivers a range of glyphs rendered as SDFs (signed distance fields) in a protocol buffer. Prior to version 0.7.7, a crafted font could trigger a heap out-of-bounds write in RenderSDF (include/mapbox/glyph_foundry_impl.hpp). RenderSDF computed the SDF bitmap allocation size as buffered_width * buffered_height in 32-bit unsigned int. Glyph dimensions are derived from the uploaded font's outline bounding box with no upper bound, so a glyph large enough to make that product exceed 2³² wrapped to a small value. The buffer was then under-allocated while the render loop still wrote one byte per pixel, corrupting the heap (CWE-190 → CWE-787) and crashing the process. A 680-byte font is enough to drive FreeType to a 65536×65536 buffered glyph, wrapping the size to 0. This issue has been patched in version 0.7.7.
Quoted source text, attributed separately from HOL analysis.