Pillow is a Python imaging library. Prior to 13.0.0, Pillow's TIFF encoder can read beyond a ColorMap buffer when retained TIFF metadata has a plane size inconsistent with BitsPerSample. A small TIFF can be opened normally and then retain a crafted ColorMap that is reused when the image is saved. An application that re-encodes the attacker's TIFF with libtiff can trigger the out-of-bounds read. This can disclose heap memory in the output or crash the process. This issue is fixed in version 13.0.0.
https://github.com/python-pillow/Pillow/security/advisories/GHSA-pchr-8j38-3x4p
https://github.com/python-pillow/Pillow/releases/tag/13.0.0
https://github.com/python-pillow/Pillow/commit/d03dc3c587a9b0bdc9e4304d70d59a635a87b742
Published: 2026-10-19
Updated: 2026-10-20
Named Vulnerability: GHSA-pchr-8j38-3x4p
Base Score: 4.3
Vector: CVSS2#AV:N/AC:M/Au:N/C:N/I:N/A:P
Severity: Medium
Base Score: 5.5
Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Severity: Medium
Base Score: 8.8
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N
Severity: High
EPSS: 0.00291