CVE-2026-96638

Pillow is a Python imaging library. From 9.1.0 until 13.0.0, BmpRleDecoder.decode() in src/PIL/BmpImagePlugin.py permits crafted RLE BMP delta escapes and absolute-mode runs to append beyond the remaining dest_length without a per-branch cap. A delta can add roughly 255 image rows in one iteration, so a kilobyte-sized file with a large but permitted width can expand the data bytearray to hundreds of megabytes or more, causing memory-exhaustion denial of service. This issue is fixed in version 13.0.0.

Score

CVSS 3.1 6.5 Medium

Status

Analyzed - security-advisories@github.com

Published

2026-10-21

Last modified

2026-10-28

Weaknesses

CWE-400, CWE-770

Affected products

• Pillow (Python)
• Pillow (Python-pillow)

References

• https://github.com/python-pillow/Pillow/security/advisories/GHSA-24rc-8hj2-v98c
• https://github.com/python-pillow/Pillow/pull/10015
• https://github.com/python-pillow/Pillow/commit/e7794835e323ff2691d9b3a974cade1a44301b9a
• https://github.com/python-pillow/Pillow/releases/tag/13.0.0