In the Linux kernel, the following vulnerability has been resolved: thunderbolt: Make the DP tunnel activation callback mandatory… (CVE-2026-98692)

The Linux kernel Thunderbolt driver had a vulnerability where the DP tunnel activation callback was optional in tb_tunnel_alloc_dp(). Without the callback, tb_dp_dprx_start() read DPRX capabilities synchronously and never queued the work, but still took a tunnel reference that was only released by asynchronous work or cancellation. This caused a reference leak for tunnels without a callback, specifically those from tb_tunnel_discover_dp() used during hibernation restore. The fix makes the callback mandatory, removes the synchronous read path, and ensures DPRX capabilities are always read asynchronously, preventing reference leaks and reducing hibernation restore delays.

The vulnerability caused a resource leak (tunnel reference leak) in the Thunderbolt DP tunnel handling, which could degrade system stability or performance over time. It also caused hibernation restore to block for up to 12 seconds, impacting user experience. There is no indication of direct security compromise or exploitation in the wild.

An official fix has been applied to the Linux kernel to make the DP tunnel activation callback mandatory and remove the synchronous capability read path. Users should update to the fixed Linux kernel version once available. No additional mitigation steps are indicated.