CVE-2026-53337

In the Linux kernel, the following vulnerability has been resolved:

net: bonding: fix NULL pointer dereference in bonddoioctl()

In bonddoioctl(), slave_dev is obtained via __devgetbyname() which can return NULL if the requested interface name does not exist. However, the subsequent slavedbg() call is placed before the NULL check:

slave_dev = __dev_get_by_name(net, ifr->ifr_slave);
slave_dbg(bond_dev, slave_dev, "slave_dev=%p:\n", slave_dev); //here
if (!slave_dev)
    return -ENODEV;

The slavedbg() macro expands to netdevdbg(bonddev, "(slave %s): " fmt, (slavedev)->name, ...) which unconditionally dereferences slave_dev->name before the NULL check is performed. This results in a NULL pointer dereference kernel oops when a user calls bonding ioctl (e.g. SIOCBONDENSLAVE, SIOCBONDRELEASE, etc.) with a non-existent slave interface name.

This is reachable from userspace via the bonding ioctl interface with CAPNETADMIN capability, making it a potential local denial-of-service vector.

Fix by moving the slave_dbg() call after the NULL check.