CVE-2026-28231
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.
Does this matter?
Lower severity and a low EPSS score (0.63%). Track it; it rarely justifies an emergency change on its own.
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.
- CVSS 4.0
- 5.5 MEDIUMCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
- EPSS
- 0.63% probability · 48th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-125, CWE-190
- Affected
- bigcat88/pillow-heif
- Source
- security-advisories@github.com
References
- https://github.com/bigcat88/pillow_heif/commit/8305a15d3780c533b762578cbe987d27a2c59c7aPatch
- https://github.com/bigcat88/pillow_heif/releases/tag/v1.3.0Product, Release Notes
- https://github.com/bigcat88/pillow_heif/security/advisories/GHSA-5gjj-6r7v-ph3xExploit, Mitigation, Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.