CVE-2025-8843 in Netwide Assember
Summary
by MITRE • 08/11/2025
A vulnerability was found in NASM Netwide Assember 2.17rc0. This affects the function macho_no_dead_strip of the file outmacho.c. The manipulation leads to heap-based buffer overflow. Local access is required to approach this attack. The exploit has been disclosed to the public and may be used.
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Analysis
by VulDB Data Team • 09/15/2025
The vulnerability identified as CVE-2025-8843 represents a critical heap-based buffer overflow in NASM Netwide Assembler version 2.17rc0, specifically within the macho_no_dead_strip function located in the outmacho.c source file. This flaw constitutes a serious security weakness that can potentially compromise system integrity and execute arbitrary code under specific conditions. The vulnerability's impact is particularly concerning given that NASM is widely used for developing low-level system software, firmware, and embedded applications where assembly language precision is paramount. The buffer overflow occurs during the processing of Mach-O binary format output generation, making it particularly dangerous for developers working on macOS and iOS platform applications.
The technical exploitation of this vulnerability requires local access to the system where NASM is installed, as the heap-based buffer overflow can be triggered through malformed input processing within the assembler's Mach-O output handling routines. The flaw stems from inadequate bounds checking in the macho_no_dead_strip function, which fails to properly validate the size of data being written to heap-allocated memory regions. This allows an attacker with local privileges to manipulate input parameters that flow into the vulnerable code path, potentially leading to memory corruption that could be leveraged for privilege escalation or arbitrary code execution. The vulnerability aligns with CWE-121, heap-based buffer overflow, and represents a classic example of improper input validation in memory management operations.
From an operational standpoint, this vulnerability poses significant risks to software development environments where NASM is utilized for building system-level applications, particularly in contexts involving macOS and iOS development. The public disclosure of exploitation techniques means that threat actors can readily develop and deploy malicious payloads targeting systems running affected versions of NASM. Organizations that rely on NASM for creating firmware, system utilities, or embedded software components face potential compromise through this vulnerability. The local access requirement does not mitigate the risk significantly, as many development environments and build servers may have elevated privileges or contain sensitive development artifacts that could be exploited. This vulnerability also intersects with ATT&CK technique T1059.008, which covers the use of command-line interfaces, as attackers could leverage the compromised assembler to execute malicious code during the build process.
The mitigation strategies for CVE-2025-8843 primarily involve immediate software updates to the latest stable version of NASM where the buffer overflow has been patched and properly validated. System administrators should implement strict access controls and privilege separation to limit local user access to systems running NASM, particularly in shared development environments. Additional protective measures include implementing input sanitization routines for any data processed through the assembler, conducting regular security audits of build environments, and monitoring for unauthorized modifications to the assembler installation. Organizations should also consider implementing runtime protection mechanisms such as stack canaries and address space layout randomization to complicate exploitation attempts. The vulnerability demonstrates the importance of maintaining current security patches and highlights the critical need for secure coding practices in development tools, particularly those handling binary output generation and memory management operations.