Security updates for macOS Ventura, macOS Monterey, and macOS Big Sur have been released to address the security vulnerabilities found in these systems. Four critical severity vulnerabilities are included in these updates, all with a CVSS base score of 9.8/10. Not a lot of information is currently available about these flaws, as Apple doesn’t disclose details until users have had a chance to patch their systems in order to best protect their customers from falling victim to attacks. These four critical severity vulnerabilities are found in the dcerpc (Distributed Computing Environment / Remote Procedure Calls) of affected macOS products, which is used by processes to communicate over a network. 

CVE-2023-27934 is a memory initialisation vulnerability where the product has not initialised or has incorrectly initialised a resource, resulting in this resource being in an unexpected state when accessed or used. A potential exploit of this vulnerability would allow a remote user to cause denial of service through terminating the app or perform arbitrary code execution. In the same way, CVE-2023-27935 can also be exploited to result in app termination or code execution by a remote attacker. This vulnerability has been resolved with improved bounds checks in the new updates, suggesting it is an out-of-bounds write vulnerability. 

The two vulnerabilities CVE-2023-27958 and CVE-2023-27953 are both associated with the same dcerpc issue affecting kernel memory. These are likely to be memory corruption vulnerabilities, as they have been solved in the new security updates through improved memory handling. This vulnerability type allows for read and write functions to be performed outside the boundary of the memory buffer, which can result in arbitrary code execution. These vulnerabilities could be exploited by a remote attacker, who could cause the system to terminate, or cause a corruption in the kernel memory.  

All of Apple’s latest security updates releases can be found listed on their website including software versions and release dates. Users should update their systems to the latest security version in order to patch all known vulnerabilities before they are able to be exploited. Security bulletins have been released by Apple to detail the content of these new security updates, including the CVEs that have been resolved, for macOS Ventura 13.3, macOS Monterey 12.6.4, and macOS Big Sur 11.7.5.