Use-After-Free Vulnerability in Linux Kernel Affecting Networking Components

CVE-2025-40297

What is CVE-2025-40297?

A use-after-free vulnerability has been identified in the Linux kernel's networking components related to the bridge subsystem. This issue occurs during a race condition where the system attempts to delete an expired Forwarding Database (fdb) entry while learning processes are still active. If Multiple Spanning Tree (MST) protocol is enabled and VLAN filtering is disabled, it may allow fdb learning to occur after a port has been marked for deletion. The vulnerability has been addressed by implementing a check for the port's VLAN group during the deletion process. This check ensures that the state bypass does not happen, preserving the integrity of network operations and preventing unauthorized learning.

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