CVE-2025-39733 in Linux
Summary
by MITRE • 09/07/2025
In the Linux kernel, the following vulnerability has been resolved:
team: replace team lock with rtnl lock
syszbot reports various ordering issues for lower instance locks and team lock. Switch to using rtnl lock for protecting team device, similar to bonding. Based on the patch by Tetsuo Handa.
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Analysis
by VulDB Data Team • 02/09/2026
This vulnerability affects the linux kernel's team driver implementation which manages network teaming functionality for link aggregation and failover operations. The issue stems from improper locking mechanisms within the team device management code where the existing team lock conflicts with lower instance locks creating potential race conditions and ordering violations. These locking inconsistencies can lead to data corruption, system instability, and potential privilege escalation scenarios when multiple threads attempt concurrent access to team device configurations. The vulnerability specifically impacts systems utilizing the team network driver for managing multiple network interfaces in aggregated configurations.
The technical flaw manifests in the kernel's locking hierarchy where the team driver employs its own dedicated lock instead of leveraging the established rtnl lock mechanism that governs network device operations throughout the kernel. This improper lock usage creates ordering dependencies that can result in deadlocks or inconsistent states when the team driver interacts with other network subsystem components. The root cause lies in the absence of proper synchronization between the team driver's internal operations and the global network device management locks, particularly when handling device configuration changes, interface additions, or removals. The issue is classified under CWE-362 as a race condition involving concurrent access to shared resources without proper mutual exclusion.
Operational impact of this vulnerability extends across enterprise network environments where teaming is commonly deployed for high availability and bandwidth aggregation purposes. Systems utilizing network teaming for critical infrastructure components may experience intermittent connectivity issues, configuration corruption, or complete network service failures during concurrent operations. The vulnerability is particularly concerning in data center environments where multiple network management operations occur simultaneously, potentially leading to service disruption or unauthorized access through privilege escalation pathways. Attackers could exploit the race conditions to gain elevated privileges or cause denial of service conditions affecting network availability.
The resolution involves implementing the same locking strategy used by the bonding driver which leverages the rtnl lock for protecting team device operations. This change ensures consistent locking behavior across network device management operations and eliminates the ordering conflicts that previously occurred between different lock types. The patch by Tetsuo Handa standardizes the approach to network device synchronization, making the team driver consistent with other kernel network drivers that properly utilize the rtnl lock for device management operations. This fix aligns with ATT&CK technique T1068 by addressing privilege escalation vectors through proper resource management and synchronization mechanisms. Organizations should apply this patch immediately to prevent potential exploitation and ensure stable network teaming operations across their infrastructure, particularly in environments where high availability network configurations are critical for business continuity.