It's essential to understand that security vulnerabilities can have severe consequences if left unaddressed. A newly discovered vulnerability, CVE-2023-21896, within the Oracle Solaris product of Oracle Systems, specifically the NSSwitch component, is raising concerns for system administrators and users globally. This vulnerability affects Oracle Solaris versions 10 and 11 and can lead to a full takeover of Oracle Solaris. This post will explore CVE-2023-21896, its impact, and potential exploitation in detail to ensure you can take the necessary steps to protect your systems.


The vulnerability in question (CVE-2023-21896) exists within the NSSwitch component of Oracle Solaris. NSSwitch is responsible for managing various databases related to system configuration and user account information. This vulnerability allows a low privileged attacker with access to the infrastructure where Oracle Solaris is running to compromise Oracle Solaris.

Exploit Details

Although CVE-2023-21896 is relatively challenging to exploit, successful attacks can lead to complete system takeover and have severe consequences for confidentiality, integrity, and availability. The CVSS 3.1 Base Score for this vulnerability is 7., with a CVSS Vector of (CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H).

To better illustrate the nature of this vulnerability, consider the following example

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <nsswitch.h>

int main(int argc, char **argv) {
  char userInput[500];
  char buffer[128];
  strncpy(buffer, userInput, sizeof(buffer));
  return ;

The code above demonstrates a scenario where the application reads user input (a potentially unsafe operation) and copies it into a buffer without checking its size. An attacker exploiting this unsafe behavior might provide a specially crafted input to overwrite memory areas, resulting in a compromise of Oracle Solaris.

Original References

For more information regarding CVE-2023-21896, consider examining the original sources provided below:

- NVD (National Vulnerability Database): CVE-2023-21896
- Oracle Critical Patch Update Advisory: Oracle CPU October 2023 (likely to contain information once released)


Oracle Systems has yet to issue a patch for this vulnerability. However, you can follow some best practices to minimize your risk:


CVE-2023-21896 is a significant vulnerability within the Oracle Solaris product that can result in the complete takeover of the affected system. By understanding the nature of this vulnerability and following the recommended mitigations, you can reduce your risk and help ensure the security of your infrastructure. Stay vigilant and keep an eye out for patches released by Oracle Systems to address this critical vulnerability fully.


Published on: 04/18/2023 20:15:00 UTC
Last modified on: 04/18/2023 20:37:00 UTC