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

{
    "lastseen": "",
    "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.",
    "published": "2026-04-18T01:39:48.056Z",
    "modified": "2026-04-18T01:39:48.056Z",
    "type": "cve",
    "title": "SAIL has heap buffer overflow in XWD decoder \u2014 bits_per_pixel vs pixmap_depth type confusion in byte-swap",
    "source": "GitHub_M",
    "references": "https://github.com/HappySeaFox/sail/security/advisories/GHSA-526v-vm72-4v64\nhttps://github.com/HappySeaFox/sail/commit/36aa5c7ec8a2bb35f6fb867a1177a6f141156b02",
    "id": "CVE-2026-40492",
    "bulletinFamily": "",
    "cwe": [
        "CWE-787"
    ],
    "cvelist": null,
    "sourceData": "HappySeaFox sail < 36aa5c7ec8a2bb35f6fb867a1177a6f141156b02",
    "sourceHref": "",
    "cvss": {
        "score": 9.8,
        "severity": "CRITICAL",
        "vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
        "version": "3.1"
    },
    "cvss2": [],
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        "baseScore": 0,
        "baseSeverity": "",
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        "privilegesRequired": "",
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        "confidentialityImpact": "",
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        "availabilityImpact": "",
        "cvssV3": {
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    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "sail",
    "version": "< 36aa5c7ec8a2bb35f6fb867a1177a6f141156b02",
    "vendor": "HappySeaFox",
    "ai_description": "Heap buffer overflow in XWD decoder due to type confusion between bits_per_pixel and pixmap_depth",
    "ai_severity": "Critical",
    "ai_vendor": "HappySeaFox",
    "ai_product": "SAIL",
    "ai_version": "< 36aa5c7ec8a2bb35f6fb867a1177a6f141156b02",
    "ai_score": 9.8
}