CVE-2026-46165: openvswitch: vport: fix self-deadlock on release of tunnel ports

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-05-28 · updated 2026-10-30
Weakness: CWE-667

Description

In the Linux kernel, the following vulnerability has been resolved: openvswitch: vport: fix self-deadlock on release of tunnel ports vports are used concurrently and protected by RCU, so netdev_put() must happen after the RCU grace period. So, either in an RCU call or after the synchronize_net(). The rtnl_delete_link() must happen under RTNL and so can't be executed in RCU context. Calling synchronize_net() while holding RTNL is not a good idea for performance and system stability under load in general, so calling netdev_put() in RCU call is the right solution here. However, when the device is deleted, rtnl_unlock() will call netdev_run_todo() and block until all the references are gone. In the current code this means that we never reach the call_rcu() and the vport is never freed and the reference is never released, causing a self-deadlock on device removal. Fix that by moving the rcu_call() before the rtnl_unlock(), so the scheduled RCU callback will be executed when synchronize_net() is called from the rtnl_unlock()->netdev_run_todo() while the RTNL itself is already released.

Affected products

Linux kernel: from 6.1.168 before 6.1.175; from 6.6.131 before 6.6.140; from 6.12.80 before 6.12.88; from 6.18.21 before 6.18.30; from 6.19.11 before 7.0; from 7.0.1 before 7.0.7 — fixed in 6.1.175, 6.6.140, 6.12.88, 6.18.30, 7.0, 7.0.7
Linux: from 6.1.168 before 6.1.175; from 6.6.131 before 6.6.140; from 6.12.80 before 6.12.88; from 6.18.21 before 6.18.30; from 6.19.11 before 6.20 — fixed in 6.1.175, 6.6.140, 6.12.88, 6.18.30, 6.20

How to fix

Upgrade to a fixed version: Linux kernel 6.1.175, 6.6.140, 6.12.88, 6.18.30; Linux 6.1.175, 6.6.140, 6.12.88, 6.18.30. Check the vendor advisory for mitigations.

References

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