critical9.1
CVE-2026-28231
pillow-heif: Integer Overflow in Encode Path Buffer Validation Leads to Heap Out-of-Bounds Read
Impact
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.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| pip | pi-heif | < 1.3.0 | 1.3.0 |
| pip | pillow-heif | < 1.3.0 | 1.3.0 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Bigcat88 | Pillow-Heif | before 1.3.0 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-5gjj-6r7v-ph3x
- https://github.com/bigcat88/pillow_heif/security/advisories/GHSA-5gjj-6r7v-ph3x
- https://nvd.nist.gov/vuln/detail/CVE-2026-28231
- https://github.com/bigcat88/pillow_heif/commit/8305a15d3780c533b762578cbe987d27a2c59c7a
- https://github.com/bigcat88/pillow_heif/releases/tag/v1.3.0
- https://github.com/pypa/advisory-database/tree/main/vulns/pi-heif/PYSEC-2026-2248.yaml
- https://github.com/pypa/advisory-database/tree/main/vulns/pillow-heif/PYSEC-2026-2258.yaml