Description

A major bug in 7-Zip lets hackers crash computers using specially designed RAR5 files. This issue, known as CVE-2025-53816, affects how 7-Zip reads RAR5 files and can cause memory problems and system crashes. Security expert Jaroslav Loba?evski found the problem in 7-Zip version 24.09. It’s caused by a memory error in the part of the software that handles RAR5 files. A serious bug in 7-Zip version 24.09 was found by researcher Jaroslav Loba?evski. It happens when the software tries to fix broken RAR5 files by filling missing parts with zeros. Due to a mistake in how memory is handled, it writes data outside the allowed area, causing a crash. The problem is caused by a miscalculation in the memory cleanup function, which leads to heap memory corruption. What makes it worse is that attackers can control the data that affects how much memory gets overwritten. This flaw mainly causes denial-of-service attacks, not code execution. When a malicious RAR5 file is opened, it crashes the app by overwriting memory with zeros. Tests showed that both official and debug versions of 7-Zip are affected.A test file proved the issue by crashing the app when run with the command 7zz e [-]so rar-crash[.]rar5. The bug is known as CWE-122, a type of memory error. It was reported on April 24, 2025, and fixed quickly.