CVE-2026-112403: python-pillow pillow Heap-based Buffer Overflow

Vulnerability summary

CVE-2026-112403 is a critical (CVSS 9.2) Heap-based Buffer Overflow vulnerability in python-pillow pillow. EPSS estimates a 0.32% chance of exploitation in the next 30 days, higher than 23.8% of scored vulnerabilities.

Timeline

1. 19-10-2026
   PublishedVulnerability first disclosed.

Description

Pillow is a Python imaging library. Prior to 13.0.0, Pillow's JPEG decoder can write a full-width scanline into a buffer sized for a requested draft scale. ImagingJpegDecode does not verify libjpeg's actual output width and component count after scaling is requested, and an 8-bit lossless SOF3 JPEG decoded by a build linked to libjpeg-turbo 3.x can ignore the requested downscaling geometry. An attacker can supply such a JPEG to an application that uses draft() or thumbnail() to request downscaling. This can corrupt heap memory, crash the process, or potentially allow code execution. Older libjpeg-turbo 2.x and IJG builds reject the SOF3 input. This issue is fixed in version 13.0.0.

• CWE-122Heap-based Buffer OverflowA heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().