Description
libschrift through 0.10.2 contains a divide by zero vulnerability that allows attackers to crash applications by supplying a font with unitsPerEm of 0 in the head table. Attackers can provide a crafted TrueType font whose NaN glyph coordinates bypass clip_points(), causing an out-of-bounds raster read in draw_line() during sft_render() and crashing the process.
Metrics
CVSS 3.1 5.5/10
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:HWeakness enumeration
Affected software
| Vendor | Product | Versions |
|---|---|---|
| tomolt | libschrift | <= 0.10.2 |
References
- https://github.com/tomolt/libschrift/blob/v0.10.2/schrift.c#L1422-L1503
- https://github.com/tomolt/libschrift/blob/v0.10.2/schrift.c#L542
- https://github.com/tomolt/libschrift/issues/46
- https://hackmd.io/@haind-pwn/libschrift-unitsperem-zero-oob
- https://www.vulncheck.com/advisories/libschrift-through-0.10.2-divide-by-zero-via-unitsperem-in-draw-line
- https://github.com/tomolt/libschrift/issues/46
- https://hackmd.io/@haind-pwn/libschrift-unitsperem-zero-oob
Timeline
- Published
- Oct 14, 2026
- Last modified
- Oct 26, 2026
- NVD status
- Deferred