CVE-2026-28231
Critical
Description
pillow_heif is a Python library for working with HEIF images and plugin for Pillow. Prior to version 1.3.0, an integer overflow in the encode path buffer validation of `_pillow_heif.c` allows an attacker to bypass bounds checks by providing large image dimensions, resulting in a heap out-of-bounds read. This can lead to information disclosure (server heap memory leaking into encoded images) or denial of service (process crash). No special configuration is required — this triggers under default settings. Version 1.3.0 fixes the issue.
SeverityCritical
CVSS9.1
Exploit probability—
ProductBigcat88 Pillow-heif
PublishedFeb 27, 2026
First seenFeb 27, 2026
Weakness typeCWE-125Out-of-bounds readCWE-190Integer overflow
How to fix
Update
- bigcat88 pillow-heif1.3.0 or later
- pi-heif1.3.0 or later
- pillow-heif1.3.0 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| bigcat88 pillow-heif | v < 1.3.0 | 1.3.0 |
| pi-heifPyPI | v < 1.3.0 | 1.3.0 |
| pillow-heifPyPI | v < 1.3.0 | 1.3.0 |
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