Resource exhaustion in Python-Pillow Pillow
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.
Vulnerability class: DoS (Denial of Service)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
- Python-Pillow Pillow — versions >= 9.1.0, < 13.0.0
Weakness classification (CWE)
References
Frequently asked questions
- What is CVE-2026-96638?
- CVE-2026-96638 is a medium-severity vulnerability in Python-Pillow Pillow, classified under Uncontrolled Resource Consumption. CVSS score: 6.5/10. Published 2026-10-21.
- How severe is CVE-2026-96638?
- Medium severity. CVSS v3 base score is 6.5 out of 10.