CVE-2026-53337

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

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

In bond_do_ioctl(), slave_dev is obtained via __dev_get_by_name() which can return NULL if the requested interface name does not exist. However, the subsequent slave_dbg() 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 slave_dbg() macro expands to netdev_dbg(bond_dev, (slave %s): fmt, (slave_dev)->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 CAP_NET_ADMIN capability, making it a potential local denial-of-service vector.

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

Affected Software

References

• https://git.kernel.org/stable/c/1b7558c85493467b2ea20738866b822db6442034
• https://git.kernel.org/stable/c/66693957bacd1c9dae6188a7312d6be69a221f2d
• https://git.kernel.org/stable/c/a629418d463fb50d132a1aa063b0105857311e5f
• https://git.kernel.org/stable/c/a764b0e8317a863006e05732e1aefe821b9d8c2d
• https://git.kernel.org/stable/c/b02b2e3e876c18733b868a29064abd11cdbf8feb
• https://git.kernel.org/stable/c/b0878106ddc486375084145848ff255dedfff46a
• https://git.kernel.org/stable/c/bcb8fad90f27300add583a8371db504b766d95c7
• https://git.kernel.org/stable/c/c2cfe290fdb1c32a4f4eb2b8ca3f363b305d21ba