CVE-2026-42309 MEDIUM

CVE-2026-42309: Pillow: Heap buffer overflow with nested list coordinates

Vendor Python-Pillow
Product Pillow
Weakness CWE-122
Published May 9, 2026
Last update May 11, 2026

CVSS base score

5.1/10
Attack vector Local
Attack complexity Low
Privileges required None
User interaction None
Confidentiality
Integrity

CVSS vector

CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

What the vulnerability does

01Description

Pillow is a Python imaging library. From version 11.2.1 to before version 12.2.0, passing nested lists as coordinates to APIs that accept coordinates such as ImagePath.Path, ImageDraw.ImageDraw.polygon and ImageDraw.ImageDraw.line could cause a heap buffer overflow, as nested lists were recursively unpacked beyond the allocated buffer. Coordinate lists are now validated to contain exactly two numeric coordinates. This issue has been patched in version 12.2.0.

Key dates

02Disclosure timeline

May 9, 2026 CVE published
May 11, 2026 Record updated