High 8.2Published Jul 14, 2026

CVE-2026-59197Pillow: Heap out-of-bounds write in Pillow `ImageFilter.RankFilter` via integer overflow in `ImagingExpand`

Updated under an hour ago (Oct 27, 2026, 12:10 PM ET)

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Exploited in the last 30 days

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.

CVSS: 8.2 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H
Weakness (CWE): CWE-787, CWE-190
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Modified
Record last updated: Jul 21, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

python-pillow Pillow python_pillow:pillow (from the name)	before 12.3.0	CNA record
python pillow python:pillow	before 12.3.0	NVD

References

References

https://github.com/python-pillow/Pillow/security/advisories/GHSA-xj96-63gp-2gmr	x-refsource-confirm, exploit, vendor-advisory
https://github.com/python-pillow/Pillow/pull/9695	x-refsource-misc, issue-tracking, patch
https://github.com/python-pillow/Pillow/commit/cce3bdb867c77a3420261ed1bfdb6b0787ec8fc1	x-refsource-misc, patch
https://github.com/python-pillow/Pillow/releases/tag/12.3.0	x-refsource-misc, release-notes

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.