CVE-2026-59959: SAIL: WebP decoder division by zero through malformed animated canvas metadata

SAIL is a cross-platform library for loading and saving images with support for animation, metadata, and ICC profiles. Prior to version 1.0.2, the built-in WebP decoder can crash during loader initialization when processing a malformed animated WebP file with inconsistent container or ANMF frame metadata. In sailcodecloadinitv8webp() in src/sail-codecs/webp/webp.c, WebPDemuxGetI with WEBPFFCANVASWIDTH can return a zero imagelocal->width, which is then used as a divisor when calculating bytesperpixel from the image row size. The division happens before frame decoding and before generic image skeleton validation in src/sail/sailadvanced.c, causing an arithmetic fault and process termination. Applications accepting untrusted WebP images can consequently suffer denial of service; builds must include the affected WebP codec. This issue is fixed in version 1.0.2.