kTLS, or Kernel TLS, is a Linux feature that moves part of Transport Layer Security processing from user space into the kernel. It is mainly used to speed up encrypted traffic by handling some send or receive work closer to the network stack, reducing copying and overhead for applications that move a lot of data.
It matters because a bug in kTLS can affect the host layer shared by many services, not just one application. Security flaws in the TLS receive path can lead to crashes, memory corruption, or other serious failures depending on the defect. In real attacks, that makes kTLS bugs attractive targets when attackers look for high-value kernel code paths. Defenders should inventory where kTLS is enabled, track vendor kernel backports, and patch quickly; if the feature is not needed, disabling it can reduce exposure.