CVE-2026-22801 is a vulnerability in the widely used libpng library, which handles PNG image files. The flaw exists in the simplified write API functions png_write_image_16bit and png_write_image_8bit, where an integer truncation error leads to a heap buffer over-read. This occurs when the caller provides a negative row stride (used for bottom-up image layouts) or a stride value exceeding 65535 bytes. The root cause is the introduction of casts in libpng version 1.6.26 aimed at suppressing compiler warnings on 16-bit systems, which inadvertently caused improper handling of stride values. As a result, memory beyond the allocated buffer can be read, potentially causing application crashes or denial of service. The vulnerability affects all libpng versions from 1.6.26 up to but not including 1.6.54, where the issue was fixed. The CVSS v3.1 score is 6.8, reflecting a medium severity with a local attack vector, low complexity, no privileges required, and no user interaction needed. The impact is primarily on availability due to heap buffer over-read leading to crashes. There are no known exploits in the wild as of the publication date. This vulnerability is relevant to any software or systems that incorporate libpng for image processing, including desktop applications, web services, and embedded systems.

For European organizations, the primary impact of CVE-2026-22801 is the potential for denial of service in applications that utilize vulnerable libpng versions. This could disrupt business operations, especially in sectors relying heavily on image processing such as media, publishing, graphic design, and web hosting services. While the vulnerability does not directly compromise confidentiality or integrity, service interruptions could affect availability and reliability of critical systems. Systems that automatically process user-supplied PNG images, such as content management platforms or image hosting services, may be susceptible to crashes if maliciously crafted images exploit this flaw. Additionally, embedded devices or IoT products using libpng might experience stability issues. The local attack vector limits remote exploitation, but insider threats or compromised local accounts could trigger the vulnerability. Given the widespread use of libpng, organizations should assess their software dependencies and update vulnerable components to prevent operational disruptions.

European organizations should take the following specific actions: 1) Identify all software and systems using libpng versions between 1.6.26 and 1.6.53, including third-party applications and embedded devices. 2) Prioritize upgrading libpng to version 1.6.54 or later, where the vulnerability is fixed. 3) For systems where immediate patching is not feasible, implement strict input validation and filtering to block PNG images with abnormal or suspicious row stride values, although this may be challenging. 4) Monitor application logs and system stability for crashes related to image processing components. 5) Employ application whitelisting and restrict local access to trusted users to reduce the risk of local exploitation. 6) Coordinate with software vendors to ensure timely updates and patches are applied. 7) Conduct security awareness training for staff with local system access to recognize and report suspicious activity. 8) Integrate vulnerability scanning tools that detect outdated libpng versions in the software inventory. These targeted measures go beyond generic advice by focusing on dependency management, input validation, and local access controls.