CVE-2025-29769 is a high-severity heap-based buffer overflow vulnerability (CWE-122) found in libvips, a demand-driven, horizontally threaded image processing library widely used for efficient image manipulation. The vulnerability arises specifically during the heifsave operation when libvips processes certain TIFF images crafted to create a "multiband" input scenario. In this context, "multiband" refers to an internal state where the color interpretation of the input image channels cannot be determined. Although creating such multiband inputs is uncommon, it is achievable with specially crafted TIFF images containing 4 channels. When libvips attempts to convert such a 4-channel TIFF image to a HEIF format output, it incorrectly assumes the output will have 3 channels without an alpha channel. However, it proceeds to write 4 channels of data into a buffer allocated for 3 channels, causing a heap buffer overflow. This overflow can lead to process crashes and potentially enable arbitrary code execution or memory corruption. The vulnerability affects all libvips versions prior to 8.16.1, where the issue has been fixed. The CVSS 4.0 base score is 8.5 (high severity), reflecting the vulnerability's significant impact on confidentiality, integrity, and availability, combined with relatively low attack complexity but requiring local privileges (AV:L) and low privileges (PR:L). No user interaction or authentication is required beyond low privileges, and no known exploits are currently reported in the wild. The vulnerability does not require network access, limiting remote exploitation but posing a serious risk in environments where untrusted TIFF images are processed locally or in automated pipelines.

For European organizations, the impact of this vulnerability can be substantial, especially for entities relying on libvips for image processing in web services, content delivery, digital media, and document management systems. Exploitation could lead to denial of service through application crashes, disrupting business operations and potentially causing data loss or service unavailability. More critically, heap buffer overflows can be leveraged to execute arbitrary code, risking full system compromise, data breaches, or lateral movement within networks. Organizations processing untrusted or user-supplied TIFF images—such as media companies, cloud service providers, and software vendors—are particularly at risk. Given libvips' integration in popular open-source projects and commercial software stacks, the vulnerability could affect a broad range of applications. The requirement for local access and low privileges reduces the risk of remote exploitation but does not eliminate it, especially in multi-tenant or shared environments where attackers might upload malicious images for processing. The vulnerability's high impact on confidentiality, integrity, and availability underscores the need for urgent remediation to prevent potential exploitation and operational disruptions.

1. Immediate upgrade to libvips version 8.16.1 or later, where the vulnerability is patched, is the most effective mitigation. 2. Implement strict input validation and sanitization for TIFF images before processing, including rejecting or quarantining images with unusual channel configurations or metadata that could trigger multiband inputs. 3. Employ sandboxing or containerization for image processing workflows to limit the impact of potential exploitation, isolating libvips processes from critical system components. 4. Monitor logs and application behavior for crashes or anomalies during image processing that could indicate attempted exploitation. 5. Restrict local access to systems running libvips to trusted users only, minimizing the risk of low-privilege attackers triggering the vulnerability. 6. For web-facing services, enforce file upload restrictions and scanning to detect and block malicious TIFF files. 7. Conduct security reviews of dependent software and libraries that integrate libvips to ensure they are updated and configured securely. 8. Maintain up-to-date backups and incident response plans to quickly recover from potential exploitation events.