What’s Vulnerable › Vulnerabilities

CVE-2026-40492: SAIL has heap buffer overflow in XWD decoder — bits_per_pixel vs pixmap_depth type confusion in byte-swap

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-04-18 · updated 2026-10-26
• Weakness: CWE-787

Description

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.

Affected products

• SAIL Image Decoding Library: before 36aa5c7ec8a2bb35f6fb867a1177a6f141156b02

References

• https://github.com/HappySeaFox/sail/commit/36aa5c7ec8a2bb35f6fb867a1177a6f141156b02
• https://github.com/HappySeaFox/sail/security/advisories/GHSA-526v-vm72-4v64
• https://github.com/HappySeaFox/sail/security/advisories/GHSA-526v-vm72-4v64

Get alerted when CVE-2026-40492 or the next vulnerability affects your stack