High [CVE-2026-59200] Denial of service via crafted PDF stream

Pillow is a Python imaging library. From 5.1.0 until 12.3.0, PdfParser.

PdfStream.decode() in PIL/PdfParser.py calls zlib.decompress() with bufsize set to the PDF stream Length field without bounding the decompressed output size, allowing a crafted FlateDecode PDF stream to exhaust memory from a small file. This issue is fixed in version 12.3.0.

By providing a specially designed PDF file, the attacker could cause the application to exhaust available memory, leading to a denial of service (DoS). The impact is limited to denial of service via memory exhaustion.

A small crafted PDF input can force unbounded decompression, but this does not lead to code execution or information disclosure. Red Hat severity: Important — CVSS 7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

Weakness: CWE-409. Affected Red Hat products: Red Hat AI Inference Server 3.3; Red Hat OpenShift AI 3.4; Red Hat Quay 3.1; Red Hat Quay 3.12; Red Hat Quay 3.15; Red Hat Quay 3.9; Lightspeed Core; OpenShift Lightspeed; Red Hat AI Inference Server; Red Hat Enterprise Linux AI (RHEL AI) 3; Red Hat OpenShift AI (RHOAI); Red Hat Quay 3.

Under investigation: Exploit Intelligence; Red Hat Ansible Automation Platform 2; Red Hat Enterprise Linux 7; Red Hat Enterprise Linux 8; Red Hat Satellite 6. Will not fix / out of support: Red Hat AI Inference Server.