NASM parse_smacro_template Null Pointer Dereference Segfault Vulnerability Analysis

Critical Vulnerability Information Vulnerability Overview Vulnerability Type: Segmentation Fault Affected Function: Related File: Line Number: 3054 Signal: SIGSEGV (11) Technical Details Vulnerability Mechanism and Root Cause: - This segmentation fault vulnerability is caused by null pointer dereference or invalid memory access in the macro template parsing logic. - The root cause lies in insufficient pointer value validation within the function, leading to an attempt to access memory at address . Vulnerability Exploitation Process 1. The function processes malformed macro definitions. 2. Invalid radix specifiers or syntactically incorrect parameters cause the parsing logic to fail. 3. At line 3025, is recursively called to further process the corrupted state. 4. Finally, at line 3054, the program attempts to read memory from address . 5. This address points to the null page, triggering a segmentation fault. AddressSanitizer Report The report indicates a SEGV occurred at unknown address , involving invalid memory access to the null page. Proof of Concept (PoC) A corrupted assembly file named is provided, which can trigger this vulnerability. Reproduction Steps 1. Compile NASM with AddressSanitizer. 2. Execute . 3. The program will crash with a segmentation fault. Affected Versions NASM version 2.17rc8 and the latest version (888d9ab).

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NASM parse_smacro_template Null Pointer Dereference Segfault Vulnerability Analysis