CVE-2026-59197

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

Published Jul 14, 2026 CVSS 3.1 · 8.2 High EPSS < 1% KEV · Not listed
Description
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-xj96-63gp-2gmr Pillow: Heap out-of-bounds write in `ImageFilter.RankFilter` via integer overflow in `ImagingExpand`
Ubuntu USN Ubuntu USN USN-8999-1 Pillow vulnerabilities
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Python-pillow
Python-pillow pillow
Vendors & Products Python-pillow
Python-pillow pillow
Type Values Removed Values Added
Description 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.
Title Pillow: Heap out-of-bounds write in Pillow `ImageFilter.RankFilter` via integer overflow in `ImagingExpand`
Weaknesses CWE-190
CWE-787
References
Metrics cvssV3_1

{'score': 8.2, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Jul 21, 2026, 6:50 PM
Reserved
Jul 2, 2026, 7:53 PM
Status
Modified
Published
Jul 14, 2026, 5:17 PM
Modified
Oct 24, 2026, 9:10 PM
Severity
Important
Public date
Jul 14, 2026, 4:25 PM