A critical vulnerability (CVE-2023-40477) has been patched in WinRAR, enabling remote attackers to execute arbitrary code by luring victims into opening a specially crafted RAR file. The severity rating is only 7.8 though due to user deception being necessary. BleepingComputer reports: The vulnerability was discovered by researcher “goodbyeselene” of Zero Day Initiative, who reported the flaw to the vendor, RARLAB, on June 8th, 2023. “The specific flaw exists within the processing of recovery volumes,” reads the security advisory released on ZDI’s site. “The issue results from the lack of proper validation of user-supplied data, which can result in a memory access past the end of an allocated buffer.”
RARLAB released WinRAR version 6.23 on August 2nd, 2023, effectively addressing CVE-2023-40477. Therefore, WinRAR users are strongly advised to apply the available security update immediately. Apart from the RAR4 recovery volumes processing code fix, version 6.23 addresses an issue with specially crafted archives leading to wrong file initiation, which is also considered a high-severity problem.