medium6.5
CVE-2026-96638
Pillow: BMP RLE decoder memory-amplification DoS via unbounded delta escape / absolute mode
Impact
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.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| pip | pillow | >= 9.1.0, < 13.0.0 | 13.0.0 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Python | Pillow | from 9.1.0 before 13.0.0 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-24rc-8hj2-v98c
- https://github.com/python-pillow/Pillow/security/advisories/GHSA-24rc-8hj2-v98c
- https://nvd.nist.gov/vuln/detail/CVE-2026-96638
- 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