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CVE-2026-40492

CRITICAL Exploitation: PoC
9.8
CVSS 3.1
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.

Metadata

CVE ID
CVE-2026-40492
State
PUBLISHED
Assigner
GitHub_M
Reserved
2026-04-13 19:50 UTC
Published
2026-04-18 01:39 UTC
Last updated
2026-04-20 15:24 UTC
Primary CWE
CWE-787
CWE-787: Out-of-bounds Write
Vendor / Product
HappySeaFox / sail
Sources
cve.org  ·  NVD

Severity & Metrics

9.8 CRITICAL CVSS 3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
SSVC — CISA Coordinator
Exploitation
PoC
Automatable
yes
Tech. Impact
total
Affected products (1)
VendorProductPlatformVersions
HappySeaFox sail — < 36aa5c7ec8a2bb35f6fb867a1177a6f141156b02
Weakness (CWE)
CWESourceDescription
CWE-787 cna CWE-787: Out-of-bounds Write
CVSS scores (1)
ScoreSeverityVersionSourceVector
9.8 CRITICAL 3.1 cna CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
References (2)
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