CVE-2021-28455 is a security vulnerability that was discovered in April 2021. It affects the Linux kernel version 5.4 and later, as well as some other related software. The vulnerability allows an attacker with local access to a vulnerable system to gain elevated privileges, potentially leading to the ability to execute arbitrary code or modify system files. This could result in the attacker being able to take over the affected system or use it as a launching pad for further attacks.
The vulnerability was caused by a flaw in the implementation of the BPF (Berkeley Packet Filter) subsystem in the Linux kernel. BPF is used for network packet filtering and analysis, and can also be used for other purposes such as tracing and performance analysis. The flaw allowed an attacker to bypass certain security checks and execute malicious code within the kernel.
The vulnerability was publicly disclosed on May 11, 2021, after patches were released by various vendors and organizations including Red Hat, Debian, and the Linux kernel developers. It was assigned a CVSS score of 7.8 out of 10, indicating a high severity level. Users and administrators were advised to update their systems as soon as possible to mitigate the risk of exploitation. Overall, CVE-2021-28455 highlights the ongoing need for robust cybersecurity practices, including timely patching and vulnerability management.