NASM Buffer Overflow and Memory Corruption

NASM up to version 3.02rc5 contains a heap use-after-free vulnerability in response file (-@) processing that allows remote attackers without authentication to cause data corruption or denial of service. The vulnerability arises from a dangling pointer stored in the global depend_file variable that is dereferenced after the response-file buffer has been freed. A proof-of-concept exploit exists, and CISA's SSVC framework rates this as automatable with partial technical impact, indicating moderate real-world risk despite the relatively modest CVSS score of 6.5.

Stack-based buffer overflow in NASM's disasm() function enables unauthenticated denial-of-service when processing malicious assembly input. Attacker-controlled disassembly formatting triggers out-of-bounds write when string length exceeds buffer capacity, causing application crash. Affects NASM assembler version 3.02rc5. Publicly available exploit code exists. CVSS 7.5 (High) reflects network-accessible attack vector requiring no privileges or user interaction, with availability impact only.

Heap buffer overflow in Netwide Assembler (NASM) 3.02rc5 obj_directive() function enables arbitrary code execution and denial of service when processing maliciously crafted .asm files. Missing bounds validation allows attackers to corrupt heap memory through specially constructed assembly source files. Publicly available exploit code exists. Impacts NASM users assembling untrusted input files, particularly automated build systems and development environments processing external assembly code.