CVE-2026-43382: batman-adv: Avoid double-rtnl_lock ELP metric worker

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: 2026-05-08 · updated 2026-06-17
Weakness: CWE-667

Description

In the Linux kernel, the following vulnerability has been resolved: batman-adv: Avoid double-rtnl_lock ELP metric worker batadv_v_elp_get_throughput() might be called when the RTNL lock is already held. This could be problematic when the work queue item is cancelled via cancel_delayed_work_sync() in batadv_v_elp_iface_disable(). In this case, an rtnl_lock() would cause a deadlock. To avoid this, rtnl_trylock() was used in this function to skip the retrieval of the ethtool information in case the RTNL lock was already held. But for cfg80211 interfaces, batadv_get_real_netdev() was called - which also uses rtnl_lock(). The approach for __ethtool_get_link_ksettings() must also be used instead and the lockless version __batadv_get_real_netdev() has to be called.

Affected products

Linux kernel: from 5.4.291 before 5.5; from 5.10.235 before 5.10.253; from 5.15.179 before 5.15.203; from 6.1.129 before 6.1.167; from 6.6.79 before 6.6.130; from 6.12.16 before 6.12.78 — fixed in 5.10.253, 5.15.203, 5.5, 6.1.167, 6.12.78, 6.14

How to fix

Upgrade to a fixed version: Linux kernel 5.10.253, 5.15.203, 5.5, 6.1.167. Check the vendor advisory for mitigations.

References

Get alerted when CVE-2026-43382 or the next vulnerability affects your stack