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.
{
"unresolved_ranges": [
{
"cpes": [
"cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*"
],
"vendor_product": "fedoraproject:fedora",
"extracted_events": [
{
"introduced": "33"
},
{
"last_affected": "33"
}
],
"source": "CPE_STRING"
}
]
}{
"cpe": "cpe:2.3:a:python:pillow:*:*:*:*:*:*:*:*",
"extracted_events": [
{
"introduced": "0"
},
{
"fixed": "8.2.0"
}
],
"source": [
"CPE_RANGE",
"REFERENCES"
]
}[
{
"digest": {
"threshold": 0.9,
"line_hashes": [
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]
},
"target": {
"file": "src/libImaging/FliDecode.c"
},
"id": "CVE-2021-28676-0f8c3b10",
"signature_version": "v1",
"signature_type": "Line",
"source": "https://github.com/python-pillow/pillow/commit/bb6c11fb889e6c11b0ee122b828132ee763b5856",
"deprecated": false
},
{
"digest": {
"function_hash": "90249710371010666261709649153104395496",
"length": 3966.0
},
"target": {
"function": "ImagingFliDecode",
"file": "src/libImaging/FliDecode.c"
},
"id": "CVE-2021-28676-89bdf835",
"signature_version": "v1",
"signature_type": "Function",
"source": "https://github.com/python-pillow/pillow/commit/bb6c11fb889e6c11b0ee122b828132ee763b5856",
"deprecated": false
}
]
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-28676.json"
"2026-07-09T05:13:56Z"