medium6.5
CVE-2026-96636
Pillow: Decompression-bomb protection bypass via multi-frame seek() in MPO and DCX (MpoImageFile.seek / DcxImageFile.seek)
Impact
Pillow is a Python imaging library. Prior to 13.0.0, MpoImageFile.seek() and DcxImageFile.seek() reparse later MPO or DCX frames and replace self._size without rerunning Image._decompression_bomb_check(). A crafted multi-frame image can use a tiny first frame to pass Image.open() and then declare an over-limit later frame. Normal frame iteration through seek(), load(), or ImageSequence.Iterator can decode that frame and commit 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 | < 13.0.0 | 13.0.0 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Python | Pillow | before 13.0.0 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-p8hx-v2p6-rp84
- https://github.com/python-pillow/Pillow/security/advisories/GHSA-p8hx-v2p6-rp84
- https://nvd.nist.gov/vuln/detail/CVE-2026-96636
- https://github.com/python-pillow/Pillow/pull/10011
- https://github.com/python-pillow/Pillow/commit/f1acfc54c53502948d0d14121872061df931db48
- https://github.com/python-pillow/Pillow/releases/tag/13.0.0