CVE-2025-10156 is a critical vulnerability identified in the ZIP archive scanning component of the mmaitre314 picklescan tool, which is used to detect malicious Python pickle files. The vulnerability arises from improper handling of exceptional conditions, specifically when the scanner encounters a ZIP archive containing a file with a deliberately corrupted Cyclic Redundancy Check (CRC). When such a malformed ZIP file is processed, the scanner prematurely halts its analysis, erroneously considering the archive safe without fully inspecting its contents. This bypass allows an attacker to embed malicious pickle files within the ZIP archive that evade detection. If the compromised pickle file is subsequently loaded by an application relying on picklescan for security scanning, it can lead to arbitrary code execution. The vulnerability is notable because it requires no authentication or user interaction, can be exploited remotely by delivering a crafted ZIP archive, and impacts the confidentiality, integrity, and availability of affected systems. The CVSS 4.0 base score of 9.3 reflects its critical severity, with network attack vector, low attack complexity, no privileges or user interaction required, and high impact on confidentiality, integrity, and availability. No patches are currently available, and no known exploits have been reported in the wild as of the publication date.

For European organizations, this vulnerability poses a significant risk, especially those that integrate mmaitre314 picklescan into their security workflows for scanning Python pickle files within ZIP archives. The ability to bypass security scans can lead to the deployment or execution of malicious code, potentially resulting in data breaches, system compromise, or disruption of critical services. Organizations in sectors such as finance, healthcare, government, and critical infrastructure, which often rely on Python-based automation and data exchange, may be particularly vulnerable. The lack of authentication and user interaction requirements means attackers can exploit this vulnerability remotely, increasing the threat surface. Additionally, since pickle files can execute arbitrary code upon deserialization, successful exploitation could lead to full system compromise, lateral movement within networks, and persistent footholds. The absence of patches further elevates the risk, necessitating immediate mitigations to prevent exploitation.

Given the absence of official patches, European organizations should implement several targeted mitigations: 1) Temporarily disable or restrict the use of mmaitre314 picklescan for scanning ZIP archives until a patch is available. 2) Implement additional validation layers for ZIP files before scanning, such as rejecting archives with CRC errors or using alternative scanning tools that do not exhibit this vulnerability. 3) Employ network-level controls to block or scrutinize incoming ZIP files from untrusted sources, including email gateways and file transfer systems. 4) Use application whitelisting and sandboxing to limit the execution scope of pickle files, reducing the impact of potential code execution. 5) Monitor logs and alerts for unusual activity related to pickle file processing or ZIP archive handling. 6) Educate developers and security teams about the risks of deserializing untrusted pickle files and encourage the use of safer serialization formats where possible. 7) Prepare incident response plans specifically addressing potential exploitation scenarios involving pickle deserialization.