CVE-2026-96638 · GHSA-24rc-8hj2-v98c
Pillow: BMP RLE decoder memory-amplification DoS via unbounded delta escape / absolute mode
- Risk score
- 48/100
- CVSS
- 6.5 v3.1
- Exploit chance (30 days)
- 0.3%
- Published
- 21 Oct 2026
Open in the live forecast Today's forecast
What to know
- What it is
- 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…
- Affected
- pillow (pip) >= 9.1.0, < 13.0.0
- Fix
- Upgrade pillow to 13.0.0 or later.
- Exploitation
- No known exploitation
Story map
At a glance
Pillow: Amber, patch this week. Pillow has a heap buffer overflow and stale-heap disclosure in _tiffWriteProc when saving compressed TIFF data through libtiff to a target without a usable fileno(). This can crash the process and may allow code execution.
The flaws
- CVE-2026-96638: Pillow: BMP RLE decoder memory-amplification DoS via unbounded delta escape / absolute mode (CVSS 6.5 · EPSS 0%)
- CVE-2026-112393: Heap buffer overflow in _tiffWriteProc when saving TIFF to BytesIO (CVSS 9.2 · EPSS 1%)
- CVE-2026-96639: Pillow multi-frame loaders can reuse stale native image storage after mode transitions (CVSS 9.8 · EPSS 1%)
- CVE-2026-112900: Argument Injection in Ghostscript call, potentially leading into RCE (CVSS 9.2 · EPSS 0%)
The fix
Upgrade Pillow: 13.0.0 or later on your release line
Who is exposed: {'products': ['Pillow'], 'packages': ['Pillow'], 'versions': ['>= 2.0.0, < 13.0.0']}
Where it stands
- Public proof of concept
- 1 outlet covering it
How it unfolded
- 23 Oct, The Hacker News (press): Critical Flaw in Python’s Popular Pillow Image Library Allows Code Execution via a Crafted Image
Connects to
- Same weakness: Denial of service (CWE-400). 253 other warnings in 30 days
Why it is Yellow
- CVSS 6.5 medium
- On your watchlist: PyPI
Affected packages
| Package | Ecosystem | Vulnerable | Fixed in |
|---|---|---|---|
| pillow | pip | >= 9.1.0, < 13.0.0 | 13.0.0 |
References
- 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
- https://github.com/advisories/GHSA-24rc-8hj2-v98c
Original description
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.
Last activity 21 Oct 2026. Patch Forecast updates every hour.