In libsixel 1.8.6, sixel_encoder_output_without_macro (called from sixel_encoder_encode_frame in encoder.c) has a double free.
The product calls free() twice on the same memory address.
| Name | Vendor | Start Version | End Version | 
|---|---|---|---|
| Libsixel | Libsixel_project | 1.8.6 (including) | 1.8.6 (including) | 
| Libsixel | Ubuntu | bionic | * | 
| Libsixel | Ubuntu | focal | * | 
| Libsixel | Ubuntu | impish | * | 
| Libsixel | Ubuntu | kinetic | * | 
| Libsixel | Ubuntu | lunar | * | 
| Libsixel | Ubuntu | mantic | * | 
| Libsixel | Ubuntu | oracular | * | 
| Libsixel | Ubuntu | trusty | * | 
| Libsixel | Ubuntu | xenial | * |