Pillow is a Python imaging library. From 4.1.0 until 13.0.0, Pillow's MSP RLE decoder can expand a small file into an unbounded in-memory buffer. The decoder writes run-length output to BytesIO without limiting expansion to the declared image size. An attacker can supply a crafted MSP image to an application that loads its pixels. This can exhaust memory and deny service even when the declared pixel count passes the decompression-bomb check. This issue is fixed in version 13.0.0.
https://github.com/python-pillow/Pillow/security/advisories/GHSA-gg2r-wvfm-q9rx
https://github.com/python-pillow/Pillow/releases/tag/13.0.0
https://github.com/python-pillow/Pillow/commit/5dcb630b9798efd91929cb873d677aeee6ed0bb3
Published: 2026-10-19
Updated: 2026-10-20
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: 8.7
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Severity: High
EPSS: 0.00291