A high-severity WinRAR vulnerability has been identified that can be exploited to achieve remote code execution on Windows systems. The vulnerability is tracked as CVE-2023-40477 and has a CVSS severity score of 7.8 out of 10 since user interaction is required for the vulnerability to be exploited.
The vulnerability is due to improper validation of user-supplied data, which can cause memory access beyond the end of an allocated buffer. If successfully exploited, an attacker could execute code in the context of the current process. To exploit the vulnerability, a user would be required to visit a malicious webpage and open a specially crafted WINRAR file.
Rarlab, which maintains WinRAR, says the vulnerability was discovered by security researcher goodbyselene at Trend Micro’s Zero Day Initiative, which says the vulnerability exists within the processing of recovery volumes. The vulnerability has been fixed in WinRAR version 6.23.
Since WinRAR is widely used, there is considerable scope for exploitation of the flaw. Users could easily be tricked into visiting a malicious web page by a phishing email for instance, so while the vulnerability only has a CVSS score of 7.8, WinRAR users should ensure they update to the latest version as soon as possible to prevent exploitation.