CVE-2026-40492

SAIL is a cross-platform library for loading and saving images with support for animation, metadata, and ICC profiles. Prior to commit 36aa5c7ec8a2bb35f6fb867a1177a6f141156b02, the XWD codec resolves pixel format based on pixmap_depth but the byte-swap code uses bits_per_pixel independently. When pixmap_depth=8 (BPP8_INDEXED, 1 byte/pixel buffer) but bits_per_pixel=32, the byte-swap loop accesses memory as uint32_t*, reading/writing 4x the allocated buffer size. This is a different vulnerability from the previously reported GHSA-3g38-x2pj-mv55 (CVE-2026-27168), which addressed bytes_per_line validation. Commit 36aa5c7ec8a2bb35f6fb867a1177a6f141156b02 contains a patch.