CVE-2026-24857 is a heap-based buffer overflow vulnerability identified in the simsong bulk_extractor tool, a widely used digital forensics utility designed to extract features from disk images. The vulnerability arises from a flaw in the embedded unrar decompression code, specifically within the RAR PPM LZ decoding path. The function Unpack::CopyString performs an out-of-bounds write when processing specially crafted RAR archives embedded inside disk images. This leads to heap corruption, which under AddressSanitizer (ASAN) causes a crash, and in production environments may result in memory corruption or potentially remote code execution (RCE). The vulnerability affects bulk_extractor versions from 1.4 up to and including 2.1.1. The CVSS 4.0 base score is 5.5 (medium severity), reflecting that the vulnerability is remotely exploitable without authentication or user interaction, but requires a crafted RAR file embedded in a disk image. No patches or fixes are currently available, increasing the risk for organizations relying on this tool for forensic investigations. The exploitation vector involves supplying a malicious disk image containing a crafted RAR archive that triggers the heap overflow during analysis. While no known exploits are currently in the wild, the potential for RCE means attackers could leverage this flaw to execute arbitrary code on forensic workstations, undermining the integrity and confidentiality of investigations.

For European organizations, especially law enforcement, cybersecurity firms, and incident response teams that utilize bulk_extractor for forensic analysis, this vulnerability presents a significant risk. Exploitation could allow attackers to compromise forensic workstations, leading to unauthorized code execution, data manipulation, or denial of service through crashes. This undermines the reliability of forensic evidence and could disrupt investigations. The medium severity score reflects moderate impact; however, the lack of patches and the potential for RCE elevate the threat. Organizations handling disk images from untrusted or external sources are particularly vulnerable. The impact extends to the confidentiality, integrity, and availability of forensic data and systems, potentially affecting legal proceedings and cybersecurity operations across Europe.

Until an official patch is released, European organizations should implement strict controls on the handling and analysis of disk images containing RAR archives. This includes sandboxing forensic analysis environments to isolate bulk_extractor processes, employing runtime memory protection tools such as ASAN or other memory error detectors during analysis, and validating or sanitizing input disk images before processing. Organizations should restrict bulk_extractor usage to trusted personnel and environments, monitor forensic workstations for unusual behavior or crashes, and maintain up-to-date backups of forensic data. Additionally, consider alternative forensic tools that do not embed vulnerable unrar code or apply manual unpacking of RAR files outside bulk_extractor. Continuous monitoring of vendor advisories for patches or mitigations is critical. Network segmentation and endpoint protection can help contain potential exploitation attempts.