Linux kernel (net/tls): The synchronous decrypt path shared refcounting and completion state with the async path, so a

Impact

The synchronous decrypt path shared refcounting and completion state with the async path, so a decrypt that was never actually asynchronous still went through the async wake-up dance. The kernel CNA scores this as a remotely reachable high-impact issue in the record decrypt path; it is also the prerequisite for the async-decrypt use-after-free fixes that follow it.

Who can reach it

The decrypt path is driven by whatever peer is sending records to a kTLS RX socket, so exposure follows every kTLS listener on the node. Practically, patch it as part of the tls async-decrypt cluster (CVE-2024-26582 / -26583 / -26584 / -26800 / CVE-2025-40176) rather than on its own - splitting them leaves the later fixes applied on top of the state this one cleans up.

What to do

Boot a kernel carrying the linked stable commits, together with the rest of the tls async-decrypt series. Interim: disable async crypto offload for kTLS so the synchronous path is used.

References