Pillow is a Python imaging library. Prior to 12.3.0, Pillow's public rank-filter API can trigger a native heap out-of-bounds write when given a very large odd filter size because ImageFilter.RankFilter.filter() calls image.expand(size // 2, size // 2) before rank-filter size validation and ImagingExpand() computes output dimensions with unchecked signed int arithmetic. This issue is fixed in version 12.3.0.
{
"cwe_ids": [
"CWE-190",
"CWE-787"
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/59xxx/CVE-2026-59197.json",
"cna_assigner": "GitHub_M"
}{
"extracted_events": [
{
"introduced": "0"
},
{
"fixed": "12.3.0"
}
],
"cpe": "cpe:2.3:a:python:pillow:*:*:*:*:*:*:*:*",
"source": [
"CPE_RANGE",
"REFERENCES"
]
}