What’s Vulnerable › Vulnerabilities

CVE-2026-96778: Pillow: Heap buffer overflow writing JPEG comment after ICC profile fills buffer

• Severity: high (CVSS 8.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-21 · updated 2026-10-28
• Weakness: CWE-787

Description

Pillow is a Python imaging library. From 9.4.0 until 13.0.0, ImagingJpegEncode() in src/libImaging/JpegEncode.c can call jpeg_write_marker() for a JPEG COM comment when an ICC profile has exactly filled the 65536-byte encoder buffer. libjpeg writes one byte before checking the exhausted free_in_buffer counter, which then wraps and permits the attacker-controlled comment and subsequent compressed image data to overwrite adjacent heap memory. Re-saving an untrusted image as JPEG while preserving its ICC profile and forwarded comment can crash the process and may enable code execution in suitable runtime and heap layouts. This issue is fixed in version 13.0.0.

Affected products

• python-pillow Pillow: from 9.4.0 before 13.0.0 — fixed in 13.0.0
• python-pillow Pillow: from 9.4.0, < 13.0.0

How to fix

Upgrade to a fixed version: python-pillow Pillow 13.0.0. Check the vendor advisory for mitigations.

References

• https://github.com/python-pillow/Pillow/commit/02561b8dc6117d5670d4b469fecdd02c70854f9b
• https://github.com/python-pillow/Pillow/pull/10124
• https://github.com/python-pillow/Pillow/releases/tag/13.0.0
• https://github.com/python-pillow/Pillow/security/advisories/GHSA-g7cr-3p24-7wf7
• https://github.com/python-pillow/Pillow/security/advisories/GHSA-g7cr-3p24-7wf7

Get alerted when CVE-2026-96778 or the next vulnerability affects your stack