CVE-2020-21677: Saitoha Libsixel

Medium severity, CVSS 6.5. EPSS: 0.9% chance of exploitation in the next 30 days.

A heap-based buffer overflow in the sixel_encoder_output_without_macro function in encoder.c of Libsixel 1.8.4 allows attackers to cause a denial of service (DOS) via converting a crafted PNG file into Sixel format.

Affected products

• Saitoha Libsixel: version 1.8.4 only

Published 2021-08-10. Last modified 2026-06-17.