CVE-2026-31678: openvswitch: defer tunnel netdev_put to RCU release

Severity: high (CVSS 7.8 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: 2026-04-25 · updated 2026-10-30
Weakness: CWE-367

Description

In the Linux kernel, the following vulnerability has been resolved: openvswitch: defer tunnel netdev_put to RCU release ovs_netdev_tunnel_destroy() may run after NETDEV_UNREGISTER already detached the device. Dropping the netdev reference in destroy can race with concurrent readers that still observe vport->dev. Do not release vport->dev in ovs_netdev_tunnel_destroy(). Instead, let vport_netdev_free() drop the reference from the RCU callback, matching the non-tunnel destroy path and avoiding additional synchronization under RTNL.

Affected products

Linux kernel: from 4.3 before 6.1.168; from 6.2 before 6.6.131; from 6.7 before 6.12.80; from 6.13 before 6.18.21; from 6.19 before 6.19.11; 7.0-rc1, 7.0-rc2, 7.0-rc3, 7.0-rc4, 7.0-rc5 — fixed in 6.1.168, 6.6.131, 6.12.80, 6.18.21, 6.19.11
Linux: 4.3 — fixed in 7.0

How to fix

Upgrade to a fixed version: Linux kernel 6.1.168, 6.6.131, 6.12.80, 6.18.21; Linux 7.0. Check the vendor advisory for mitigations.

References

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