libsixel: Use-After-Free in load_gif()_CVE-2026-33018

{
    "lastseen": "",
    "description": "libsixel is a SIXEL encoder/decoder implementation derived from kmiya's sixel. Versions 1.8.7 and prior contain a Use-After-Free vulnerability via the load_gif() function in fromgif.c, where a single sixel_frame_t object is reused across all frames of an animated GIF and gif_init_frame() unconditionally frees and reallocates frame->pixels between frames without consulting the object's reference count. Because the public API explicitly provides sixel_frame_ref() to retain a frame and sixel_frame_get_pixels() to access the raw pixel buffer, a callback following this documented usage pattern will hold a dangling pointer after the second frame is decoded, resulting in a heap use-after-free confirmed by ASAN. Any application using sixel_helper_load_image_file() with a multi-frame callback to process user-supplied animated GIFs is affected, with a reliable crash as the minimum impact and potential for code execution. This issue has been fixed in version 1.8.7-r1.",
    "published": "2026-04-14T21:45:42.261Z",
    "modified": "2026-04-14T21:45:42.261Z",
    "type": "cve",
    "title": "libsixel: Use-After-Free in load_gif()",
    "source": "GitHub_M",
    "references": "https://github.com/saitoha/libsixel/security/advisories/GHSA-w46f-jr9f-rgvp\nhttps://github.com/saitoha/libsixel/releases/tag/v1.8.7-r1",
    "id": "CVE-2026-33018",
    "bulletinFamily": "",
    "cwe": [
        "CWE-416"
    ],
    "cvelist": null,
    "sourceData": "saitoha libsixel < 1.8.7-rc1",
    "sourceHref": "",
    "cvss": {
        "score": 7,
        "severity": "HIGH",
        "vector": "CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H",
        "version": "3.1"
    },
    "cvss2": [],
    "cvss3": {
        "version": "",
        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
            "baseSeverity": "",
            "attackVector": "",
            "attackComplexity": "",
            "privilegesRequired": "",
            "userInteraction": "",
            "scope": "",
            "confidentialityImpact": "",
            "integrityImpact": "",
            "availabilityImpact": ""
        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "libsixel",
    "version": "< 1.8.7-rc1",
    "vendor": "saitoha",
    "ai_description": "",
    "ai_severity": "",
    "ai_vendor": "",
    "ai_product": "",
    "ai_version": "",
    "ai_score": 0
}