CVE-2026-23103 ipvlan: Make the addrs_lock be per port
A race condition in the Linux kernel ipvlan driver could cause false-negative address checks or inconsistent state during IPv6 address changes.
- 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-2026-23103?
CVE-2026-23103 is a high-severity vulnerability in Linux kernel, published on 4 Feb 2026. 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:
ipvlan: Make the addrs_lock be per port
Make the addrs_lock be per port, not per ipvlan dev.
Initial code seems to be written in the assumption, that any address change must occur under RTNL. But it is not so for the case of IPv6. So
1) Introduce per-port addrs_lock.
2) It was needed to fix places where it was forgotten to take lock (ipvlan_open/ipvlan_close)
This appears to be a very minor problem though. Since it's highly unlikely that ipvlan_add_addr() will be called on 2 CPU simultaneously. But nevertheless, this could cause:
1) False-negative of ipvlan_addr_busy(): one interface iterated through all port->ipvlans + ipvlan->addrs under some ipvlan spinlock, and another added IP under its own lock. Though this is only possible for IPv6, since looks like only ipvlan_addr6_event() can be called without rtnl_lock.
2) Race since ipvlan_ht_addr_add(port) is called under different ipvlan->addrs_lock locks
This should not affect performance, since add/remove IP is a rare situation and spinlock is not taken on fast paths.
Which versions are affected by CVE-2026-23103?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-23103?
Apply the vendor's patch.
Is CVE-2026-23103 being exploited?
There is no known exploitation of CVE-2026-23103 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-77283, BELL-CVE-2026-23103, DEBIAN-CVE-2026-23103, GHSA-ghmm-m363-9645, ROOT-OS-DEBIAN-11-CVE-2026-23103, ROOT-OS-DEBIAN-12-CVE-2026-23103 and 4 more.