CVE-2021-32791 is a vulnerability in the Linux kernel's implementation of the netfilter subsystem. This flaw allows an attacker to bypass certain network traffic filtering rules by sending specially crafted packets that can evade filters and reach the targeted system. The vulnerability affects Linux systems with kernel versions 3.16 through 5.12, potentially putting millions of servers at risk.
The vulnerability was discovered on May 19th, 2021, and was reported to the Linux kernel security team. A patch for the bug was released on June 10th, 2021, just three weeks after its discovery. However, it is important to note that not all Linux distributions have implemented the patch, and some may take longer to do so.
The potential impact of this vulnerability is significant, as it could be used by attackers to bypass firewalls or other security measures and launch attacks against vulnerable systems. System administrators are advised to check whether their systems are affected and ensure that they have applied the necessary updates to mitigate the risk of exploitation.