Executive brief
The Netwide Assembler (NASM) is a popular tool used by developers to convert assembly language code into machine-readable formats. A security flaw in this tool allows a specially crafted assembly file to crash the application or potentially allow unauthorized code execution when a user attempts to process it. This could disrupt development workflows or be used as a stepping stone for further attacks on a developer's workstation.
Technical details
A heap-based buffer overflow (CWE-787) exists in NASM within the 'obj_directive()' function located in 'output/outobj.c'. The root cause is a lack of proper bounds checking when processing the 'GROUP' directive. An attacker can exploit this by providing a malicious '.asm' source file for assembly. Successful exploitation requires a user to run NASM on the malicious file, which can lead to out-of-bounds memory writes, resulting in application crashes (DoS) or potential arbitrary code execution. The vulnerability was identified in version 3.02 rc5.
Affected products
- NASM Project Netwide Assembler (NASM) 3.02 rc5
Timeline
- 2026-02-27: other: Issue reported on GitHub
- 2026-04-10: disclosed: CVE published
- 2026-04-23: advisory: NVD analysis updated