CVE-2026-74283 tipc: require net admin for TIPCv2 netlink mutators
Unprivileged local users can modify TIPC network state and keys due to missing admin permission checks in TIPCv2 netlink mutators.
- 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-2026-74283?
CVE-2026-74283 is a high-severity missing authorization vulnerability in Linux, published on 15 Aug 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:
tipc: require net admin for TIPCv2 netlink mutators
TIPCv2 registers mutating generic-netlink operations without admin permission flags. Generic netlink only checks CAP_NET_ADMIN when an operation sets GENL_ADMIN_PERM or GENL_UNS_ADMIN_PERM, so a local unprivileged process can currently change TIPC state through commands such as TIPC_NL_NET_SET, TIPC_NL_KEY_SET, TIPC_NL_KEY_FLUSH, and bearer enable/disable.
The legacy TIPC netlink API already checks netlink_net_capable(..., CAP_NET_ADMIN) for administrative commands. Give the TIPCv2 mutators the equivalent generic-netlink gate. Use GENL_UNS_ADMIN_PERM, which maps to the same namespace-aware CAP_NET_ADMIN check that netlink_net_capable() performs, so the behaviour matches the legacy path and keeps working for CAP_NET_ADMIN holders in a non-initial user namespace (containers).
A QEMU/KASAN repro run as uid/gid 65534 with zero effective capabilities previously succeeded in changing the network id and node identity, setting and flushing key material, and enabling/disabling a UDP bearer. With this patch applied the same operations fail with -EPERM.
Which versions are affected by CVE-2026-74283?
How do I fix CVE-2026-74283?
Apply the vendor's patch.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-74283 being exploited?
There is no known exploitation of CVE-2026-74283 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-74283, DEBIAN-CVE-2026-74283, GHSA-5jpm-p694-hhf9, UBUNTU-CVE-2026-74283.