CVE-2026-59959
Deferred Deferred - Pending Action

Division by Zero in SAIL WebP Decoder

Publication date: 2026-10-28

Last updated on: 2026-10-28

Assigner: GitHub, Inc.

Description
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 `sail_codec_load_init_v8_webp()` in `src/sail-codecs/webp/webp.c`, `WebPDemuxGetI` with `WEBP_FF_CANVAS_WIDTH` can return a zero `image_local->width`, which is then used as a divisor when calculating `bytes_per_pixel` from the image row size. The division happens before frame decoding and before generic image skeleton validation in `src/sail/sail_advanced.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.

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Meta Information

Published
2026-10-28
Last Modified
2026-10-28
Generated
2026-10-28
AI Q&A
2026-10-28
EPSS Evaluated
N/A
NVD
CVE-2026-59959
EUVD
EUVD-2026-112083

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
HappySeaFox sail < 1.0.2

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-369 The product divides a value by zero.

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Executive Summary

This vulnerability affects the SAIL library, which handles image loading and saving. A crash can occur when processing a malformed animated WebP file due to inconsistent metadata. The crash happens during loader initialization before proper validation, causing an arithmetic fault and process termination.

Impact Analysis

Applications using the affected SAIL library to process untrusted WebP images may crash, leading to denial of service. This impacts systems that rely on these applications for image handling, especially those accepting files from untrusted sources.

Mitigation Strategies

Update SAIL to version 1.0.2 or later to fix the WebP decoder issue. If updating is not possible, disable the WebP codec in SAIL to prevent processing of untrusted WebP images.

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