Executive brief
A vulnerability in the Linux kernel's networking component could allow a remote attacker to cause a system crash (kernel panic). This occurs when specific network traffic is processed while a network interface is being disconnected from a 'bonded' group. This issue primarily impacts system availability and could lead to service outages.
Technical details
A NULL pointer dereference exists in net/core/filter.c within the xdp_master_redirect() function. The vulnerability is caused by a race condition during the release of a bond slave; bond_upper_dev_unlink() removes the upper-master adjacency before the IFF_SLAVE flag is cleared. If an XDP_TX event occurs during this window, xdp_master_redirect() attempts to dereference the 'master' pointer returned by netdev_master_upper_dev_get_rcu() without a NULL check. This results in a kernel panic when the code attempts to read master->flags. The fix introduces a NULL check for the master device before dereferencing.
Affected products
- Linux Linux Kernel 879af96ffd72 to e82d8cc4321c
Timeline
- 2026-06-20: disclosed: Initial patch submitted by Xiang Mei
- 2026-07-24: patched: Commits merged into stable branches
- 2026-07-27: advisory: CVE-2026-64545 published
References
- https://git.kernel.org/stable/c/03b743586a2469744e96e9c1015096d07240935d
- https://git.kernel.org/stable/c/3876318ea54e83eb70982b8280a3c5e4e32269bf
- https://git.kernel.org/stable/c/4edbcacca09f92b85d3951b6add11894b20a84bc
- https://git.kernel.org/stable/c/89c103d702b25ceb2d097faf854deb47b53b17ff
- https://git.kernel.org/stable/c/c99ca049e910d61ddbd28cc2c47242f2bfbb4970
- https://git.kernel.org/stable/c/e2a56441233131fe18a76001de347ecda217e40c
- https://git.kernel.org/stable/c/e82d8cc4321c373dc46e741cd2dfdaa7921fddb7