Infinite Loop Vulnerability in Open vSwitch Affecting Linux Kernel

CVE-2025-21681

Summary

In the Linux kernel, a vulnerability was identified in Open vSwitch related to the transmission of packets to unregistering network devices. When a device is being unregistered, the 'real_num_tx_queues' can drop to zero, potentially leading to an infinite loop in the skb_tx_hash function. This condition can occur even when the device reports a carrier status of OK, particularly with the net/dummy device, which does not implement necessary state changes during unregistration. Consequently, encountering this flaw could lock the core indefinitely, and the only recourse is to reboot the system. The vulnerability has been addressed by requiring checks on both the device's running status and carrier state, ensuring better handling during the unregistration process.

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