CVE-2025-8845 is a stack-based buffer overflow vulnerability identified in the Netwide Assembler (NASM) version 2.17rc0, specifically within the assemble_file function of the nasm.c source file. NASM is a widely used assembler for the x86 architecture, commonly employed by developers, security researchers, and in various software development and reverse engineering workflows. The vulnerability arises due to improper handling of input data in the assemble_file function, which allows an attacker to overflow a buffer on the stack. This overflow can potentially overwrite adjacent memory, leading to undefined behavior such as crashes, data corruption, or execution of arbitrary code. The attack vector is local, meaning the attacker must have some level of access to the host system to exploit the vulnerability. No user interaction is required once local access is obtained, and the exploit does not require elevated privileges but does require at least low privileges on the system. The CVSS 4.0 base score is 4.8 (medium severity), reflecting limited attack scope and impact. The vulnerability has been publicly disclosed, and proof-of-concept exploits may be available, increasing the risk of exploitation. However, there are no known exploits in the wild at this time, and no official patches have been linked yet. Given the nature of NASM as a development tool, exploitation would likely target developer workstations or build servers where NASM 2.17rc0 is installed. Successful exploitation could allow an attacker to execute arbitrary code with the privileges of the NASM user, potentially leading to further system compromise or lateral movement within a network.

For European organizations, the impact of CVE-2025-8845 depends largely on the use of NASM 2.17rc0 within their development or build environments. Organizations involved in software development, embedded systems, or security research that rely on NASM could face risks of local privilege escalation or code execution if an attacker gains local access. This could lead to compromise of developer machines, theft or manipulation of source code, and potential introduction of malicious code into software supply chains. The medium severity rating indicates that while the vulnerability is not trivial, exploitation requires local access and some privileges, limiting remote attack scenarios. However, in environments with shared developer workstations or insufficient endpoint security, the vulnerability could be leveraged by insider threats or malware that gains initial foothold. The absence of known exploits in the wild reduces immediate risk, but public disclosure means attackers could develop exploits rapidly. European organizations with stringent software development lifecycle controls and endpoint protections may mitigate risk, but those with less mature security postures could be vulnerable to targeted attacks or insider misuse.

To mitigate CVE-2025-8845, European organizations should: 1) Immediately identify and inventory all systems running NASM version 2.17rc0. 2) Restrict local access to systems with NASM installed, enforcing least privilege principles and strong authentication controls to prevent unauthorized local logins. 3) Monitor and audit usage of NASM binaries to detect anomalous or unauthorized execution. 4) Apply any available patches or updates from NASM maintainers as soon as they are released; if no patch is currently available, consider downgrading to a previous stable version not affected by this vulnerability or upgrading to a newer fixed version once available. 5) Implement endpoint protection solutions capable of detecting exploitation attempts such as unusual memory operations or buffer overflow behaviors. 6) Educate developers and system administrators about the risks of running untrusted input through NASM and encourage secure coding and build practices. 7) Employ application whitelisting and sandboxing techniques to limit the impact of potential exploitation. 8) Integrate this vulnerability into vulnerability management and incident response plans to ensure timely detection and remediation.