High-severity vulnerability in Linux caused by a single errant character

Researchers have analyzed a high-severity vulnerability in Linux that’s able to escalate untrusted users to root by exploiting a bug you don't often see: a single errant character inside the kernel.

The vulnerability, tracked as CVE-2026-23111, is located in nf_tables, a subsystem of the Linux kernel that provides packet filtering capabilities. It’s used to manage firewall rules and replaces older subsystems such as iptables, ip6tables, arptables, and ebtables.

!!!WTF!!!

The presence of a single mis-issued exclamation point in code implementing nf_tables introduced a use-after-free, a class of vulnerability that corrupts memory by placing malicious code at memory addresses that haven’t been properly freed of their previous contents. CVE-2026-23111 can be exploited by an unprivileged user or process to elevate system rights to root.

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