CVE-2023-45664

stb_image is a single file MIT licensed library for processing images. A
crafted image file can trigger stbi__load_gif_main_outofmem attempt to
double-free the out variable. This happens in stbi__load_gif_main because
when the layers * stride value is zero the behavior is implementation
defined, but common that realloc frees the old memory and returns null
pointer. Since it attempts to double-free the memory a few lines below the
first “free”, the issue can be potentially exploited only in a
multi-threaded environment. In the worst case this may lead to code
execution.