CVE-2023-54012 net: fix stack overflow when LRO is disabled for virtual interfaces
A local attacker can cause a kernel stack overflow and system crash by disabling LRO on nested virtual network interfaces.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2023-54012?
CVE-2023-54012 is a high-severity denial of service vulnerability in Linux, published on 24 Dec 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
net: fix stack overflow when LRO is disabled for virtual interfaces
When the virtual interface's feature is updated, it synchronizes the updated feature for its own lower interface. This propagation logic should be worked as the iteration, not recursively. But it works recursively due to the netdev notification unexpectedly. This problem occurs when it disables LRO only for the team and bonding interface type.
team0 | +------+------+-----+-----+ | | | | | team1 team2 team3 ... team200
If team0's LRO feature is updated, it generates the NETDEV_FEAT_CHANGE event to its own lower interfaces(team1 ~ team200). It is worked by netdev_sync_lower_features(). So, the NETDEV_FEAT_CHANGE notification logic of each lower interface work iteratively. But generated NETDEV_FEAT_CHANGE event is also sent to the upper interface too. upper interface(team0) generates the NETDEV_FEAT_CHANGE event for its own lower interfaces again. lower and upper interfaces receive this event and generate this event again and again. So, the stack overflow occurs.
But it is not the infinite loop issue. Because the netdev_sync_lower_features() updates features before generating the NETDEV_FEAT_CHANGE event. Already synchronized lower interfaces skip notification logic. So, it is just the problem that iteration logic is changed to the recursive unexpectedly due to the notification mechanism.
Reproducer:
ip link add team0 type team ethtool -K team0 lro on for i in {1..200} do ip link add team$i master team0 type team ethtool -K team$i lro on done
ethtool -K team0 lro off
In order to fix it, the notifier_ctx member of bonding/team is introduced.
Which versions are affected by CVE-2023-54012?
How do I fix CVE-2023-54012?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2023-54012 being exploited?
There is no known exploitation of CVE-2023-54012 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2023-54012, DEBIAN-CVE-2023-54012, GHSA-2vmp-q8v6-7qc9, UBUNTU-CVE-2023-54012.