CVE-2025-8851 is a stack-based buffer overflow vulnerability identified in LibTIFF versions up to 4.5.1, specifically within the function readSeparateStripsetoBuffer located in the tiffcrop component (tools/tiffcrop.c). LibTIFF is a widely used open-source library for reading and writing TIFF (Tagged Image File Format) files, commonly integrated into various image processing tools and software. The vulnerability arises from improper handling of input data in the readSeparateStripsetoBuffer function, which can lead to a stack-based buffer overflow condition. This type of overflow occurs when more data is written to a buffer located on the stack than it can hold, potentially overwriting adjacent memory, including control flow data such as return addresses. Exploiting this vulnerability could allow an attacker with local access and low privileges to execute arbitrary code or cause a denial of service by crashing the affected application. The attack vector requires local access with low privileges, no user interaction, and no authentication bypass, which limits remote exploitation possibilities. The vulnerability has a CVSS 4.8 (medium) score, reflecting moderate severity due to the local access requirement and limited scope of impact. A patch has been identified (commit 8a7a48d7a645992ca83062b3a1873c951661e2b3) to address this issue, and it is recommended to update affected LibTIFF versions to mitigate the risk.

For European organizations, the impact of CVE-2025-8851 depends largely on the deployment of LibTIFF in their software stack, particularly in image processing applications or tools that utilize the tiffcrop utility. Organizations in sectors such as media, publishing, healthcare (medical imaging), and government agencies that handle TIFF images extensively may be at higher risk. The vulnerability requires local access, so the primary risk vector is from insider threats, compromised user accounts, or attackers who have already gained limited access to internal systems. Successful exploitation could lead to privilege escalation or arbitrary code execution, potentially allowing attackers to move laterally within networks or disrupt critical image processing workflows. While no known exploits are currently reported in the wild, the presence of a buffer overflow vulnerability in a widely used library necessitates proactive patching to prevent future exploitation. The medium severity rating suggests that while the threat is not critical, neglecting to address it could expose organizations to avoidable risks, especially in environments where image processing is integral to operations.

1. Immediate application of the official patch or upgrade to a LibTIFF version beyond 4.5.1 where the vulnerability is resolved. 2. Conduct an inventory of all systems and applications using LibTIFF, particularly those employing the tiffcrop tool, to identify affected instances. 3. Restrict local access permissions to systems handling TIFF images to trusted users only, minimizing the risk of exploitation by unauthorized personnel. 4. Implement strict endpoint security controls, including application whitelisting and behavior monitoring, to detect anomalous activity indicative of exploitation attempts. 5. Regularly audit and monitor logs for unusual crashes or errors related to TIFF processing utilities that might signal exploitation attempts. 6. Educate users with local access about the risks of running untrusted TIFF files or tools that could trigger the vulnerability. 7. Employ network segmentation to limit lateral movement in case of a successful local exploit. 8. Integrate vulnerability scanning into the software development lifecycle to detect outdated or vulnerable library versions proactively.