CVE-2026-74283

01/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.

02/References8

• git.kernel.org/stable/c/52864c6c13dcc292481eabfeb3c31a86c3ec06f2
• git.kernel.org/stable/c/56f0a2e0a1d004e025cd031c3a801ab73959269f
• git.kernel.org/stable/c/86b0c540e2ea397cde021eecd24145f7c16a3d4e
• git.kernel.org/stable/c/9b937de4b3ded62a24da6e8d9d623cdb2748fa74
• git.kernel.org/stable/c/b06fb5f78a9af0929aaa47c92d0b7bca0617fb25
• git.kernel.org/stable/c/c9668a4adb2264625daeeabc7466b783badd4614
• git.kernel.org/stable/c/cebaefe1aceb650d5c99a4c0e1a4dde09e211818
• git.kernel.org/stable/c/e87dcc1a644d087de0bb6c94c6dd28c29b89597f