An issue was discovered in Pillow before 8.2.0. For FLI data, FliDecode did not properly check that the block advance was non-zero, potentially leading to an infinite loop on load.
[
    {
        "id": "CVE-2021-28676-0f8c3b10",
        "deprecated": false,
        "signature_version": "v1",
        "signature_type": "Line",
        "target": {
            "file": "src/libImaging/FliDecode.c"
        },
        "digest": {
            "line_hashes": [
                "276082854084581862752233006547183163125",
                "154487951280376738261317199800104056040",
                "196791183223561229908953348714930460735",
                "108716279980050847017816890668636521998"
            ],
            "threshold": 0.9
        },
        "source": "https://github.com/python-pillow/pillow/commit/bb6c11fb889e6c11b0ee122b828132ee763b5856"
    },
    {
        "id": "CVE-2021-28676-89bdf835",
        "deprecated": false,
        "signature_version": "v1",
        "signature_type": "Function",
        "target": {
            "file": "src/libImaging/FliDecode.c",
            "function": "ImagingFliDecode"
        },
        "digest": {
            "function_hash": "90249710371010666261709649153104395496",
            "length": 3966.0
        },
        "source": "https://github.com/python-pillow/pillow/commit/bb6c11fb889e6c11b0ee122b828132ee763b5856"
    }
]