CVE-2025-66861 is a vulnerability identified in GNU BinUtils version 2.26, specifically within the function d_unqualified_name located in the cp-demangle.c source file. This function is responsible for demangling C++ symbol names, a process used to convert mangled names back into human-readable form. The vulnerability arises when the function processes a specially crafted Portable Executable (PE) file, which can cause a denial of service (DoS) condition. The underlying issue is classified under CWE-400, indicating a resource exhaustion or uncontrolled resource consumption problem. When exploited, the crafted PE file causes the BinUtils process to crash or become unresponsive, effectively denying service to legitimate users or automated processes relying on BinUtils for binary analysis or manipulation. The CVSS v3.1 base score is 2.5, reflecting a low severity primarily due to the requirement for local access (AV:L), high attack complexity (AC:H), no privileges required (PR:N), and user interaction (UI:R). The vulnerability does not impact confidentiality or integrity, only availability. No known public exploits exist at this time, and no patches have been released, suggesting the issue is newly disclosed or not yet widely exploited. BinUtils is commonly used in software development, reverse engineering, and build environments, especially on Linux systems, where PE files might be analyzed or cross-compiled. The lack of a patch means organizations must rely on mitigating controls until an official fix is available.

The primary impact of CVE-2025-66861 is a denial of service condition affecting processes using BinUtils 2.26 to handle PE files. For European organizations, this could disrupt software development workflows, automated build systems, or security analysis tools that rely on BinUtils for binary processing. Although the vulnerability requires local access and user interaction, it could be exploited by malicious insiders or through social engineering to cause targeted disruption. The absence of confidentiality or integrity impact limits the risk to data breaches or manipulation. However, availability disruptions in critical development or operational environments could delay project timelines or reduce productivity. Given the low severity and high exploitation complexity, widespread impact is unlikely, but organizations with high dependency on BinUtils in cross-platform development or malware analysis contexts should remain vigilant. The lack of patches means temporary mitigations are necessary to reduce risk until updates are available.

1. Restrict access to systems and user accounts that have BinUtils 2.26 installed, limiting usage to trusted personnel only. 2. Implement strict file handling policies to prevent untrusted or suspicious PE files from being processed by BinUtils tools. 3. Monitor system logs and process behavior for signs of crashes or hangs related to BinUtils usage, enabling rapid detection of exploitation attempts. 4. Use sandboxing or containerization to isolate BinUtils processes, minimizing the impact of potential crashes on broader systems. 5. Educate users about the risks of opening or processing untrusted PE files, reducing the likelihood of user interaction exploitation. 6. Track vendor advisories and apply patches or updates promptly once they become available to remediate the vulnerability definitively. 7. Consider upgrading to newer versions of BinUtils if they are confirmed not vulnerable or contain fixes for this issue. 8. Employ application whitelisting to control execution of BinUtils binaries and related tools.