TI-2026-22566 Aliases CVE-2026-28231 GHSA-5gjj-6r7v-ph3x

pillow_heif Has Integer Overflow in Encode Path Buffer Validation that Leads to Heap Out-of-Bounds Read

MEDIUM 64CWE-125Published 2026-02-27 · Updated 2026-03-03

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Attack requirements: None
Impact type: —
Confidentiality · integrity · availability: None · None · Low
Fix status: Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and GitHub.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV

EPSS 0.00703 53rd percentileScored 2026-11-07

Public exploit Yes 1 exploit referenceTagged by NVD

Fix Fixed pillow_heif (bigcat88): 1.3.0pi-heif (PyPI): 1.3.0+1 more product

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: Poc
Automatable: Yes
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
bigcat88	pillow_heif	before 1.3.0	1.3.0	Patch available	CNA
—	pi-heif (PyPI)	before 1.3.0	1.3.0	Patch available	GHSA-5gjj-6r7v-ph3x
—	pillow-heif (PyPI)	before 1.3.0	1.3.0	Patch available	GHSA-5gjj-6r7v-ph3x

pillow_heif Vendorbigcat88 Affected before 1.3.0 Fixed in 1.3.0 Patch available CNA
pi-heif (PyPI) Vendor— Affected before 1.3.0 Fixed in 1.3.0 Patch available GHSA-5gjj-6r7v-ph3x
pillow-heif (PyPI) Vendor— Affected before 1.3.0 Fixed in 1.3.0 Patch available GHSA-5gjj-6r7v-ph3x

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:bigcat88:pillow-heif::::::python::*	before 1.3.0	Vulnerable	bigcat88

cpe:2.3:a:bigcat88:pillow-heif:*:*:*:*:*:python:*:* Versions before 1.3.0 Vulnerable ·bigcat88

Remediation

Fix · CNA pillow_heif (bigcat88) Fixed in 1.3.0
Fix · GHSA-5gjj-6r7v-ph3x pi-heif (PyPI) Fixed in 1.3.0 Advisory →
Fix · GHSA-5gjj-6r7v-ph3x pillow-heif (PyPI) Fixed in 1.3.0 Advisory →

Timeline

2026-10-02 Threatist record created from CVE-2026-28231
2026-10-03 Alias added: GHSA-5gjj-6r7v-ph3x

References

Other 4

Sources

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