CVE-2026-96639
Pillow multi-frame loaders can reuse stale native image storage after mode transitions
- State
- Published
- Severity
- 9.8 Critical
- Published
- Oct 21, 2026
- Updated
- Oct 29, 2026
- Reserved
- Sep 23, 2026
Description
Pillow is a Python imaging library. From 11.0.0 until 13.0.0, multi-frame loaders can retain an ImagingCore allocation created for a narrow frame mode while a later frame of the same dimensions changes the logical mode and decoder tiles to wider RGB or CMYK data. ImageFile.load_prepare() reuses the stale native storage because _im is non-null without verifying that its mode and size still match. Crafted PSD, MPO, DCX, or MIC frame transitions can then write wider pixels into the narrow allocation, causing native out-of-bounds writes and crashes. The MPO path can also cause a native over-read and, in demonstrated runtime-specific profiles, command execution. This issue is fixed in version 13.0.0.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 9.8 Critical | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H | GitHub_M |
Weaknesses
Affected Products
| Product | Versions |
|---|---|
Pillowpython-pillow |
|
References
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