Local privilege escalation is a vulnerability or technique that lets someone who can already run code on a system as a limited user gain higher privileges, such as administrator or root. The word local means the attacker must already have some access to the machine, for example a user account, a shell or the ability to run a program as an unprivileged service.
These flaws are often used in combination with others. A remote code execution bug in a web application may give an attacker only the rights of the web server account, and a local privilege escalation flaw can then be used to try to gain full control of the system. Linux kernel flaws such as the one named Fragnesia, CVE-2026-46300, are examples of this class.
A local privilege escalation vulnerability on its own is generally less urgent than a remotely exploitable one, because an attacker cannot use it without existing access. It does not follow that it can be ignored, since the risk rises sharply on systems where untrusted code or users can run, such as shared servers, container hosts and internet-facing applications. Exposure also depends on the kernel or software build, the distribution and its configuration.
To limit the risk, apply operating system and kernel updates promptly, remember that a new kernel needs a reboot or a supported live patch to take effect, and run services with the least privileges they need. Separate untrusted workloads where possible, and investigate any unexpected change in the rights of an account or process as a possible sign that a system has been taken further than the first intrusion.