CVE-2026-23035 net/mlx5e: Pass netdev to mlx5e_destroy_netdev instead of priv
A local attacker with high privileges can trigger a kernel null pointer dereference in the mlx5e driver during device removal, causing a system crash.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-23035?
CVE-2026-23035 is a vulnerability in Linux, published on 31 Jan 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:
net/mlx5e: Pass netdev to mlx5e_destroy_netdev instead of priv
mlx5e_priv is an unstable structure that can be memset(0) if profile attaching fails.
Pass netdev to mlx5e_destroy_netdev() to guarantee it will work on a valid netdev.
On mlx5e_remove: Check validity of priv->profile, before attempting to cleanup any resources that might be not there.
This fixes a kernel oops in mlx5e_remove when switchdev mode fails due to change profile failure.
$ devlink dev eswitch set pci/0000:00:03.0 mode switchdev Error: mlx5_core: Failed setting eswitch to offloads. dmesg: workqueue: Failed to create a rescuer kthread for wq "mlx5e": -EINTR mlx5_core 0012:03:00.1: mlx5e_netdev_init_profile:6214:(pid 37199): mlx5e_priv_init failed, err=-12 mlx5_core 0012:03:00.1 gpu3rdma1: mlx5e_netdev_change_profile: new profile init failed, -12 workqueue: Failed to create a rescuer kthread for wq "mlx5e": -EINTR mlx5_core 0012:03:00.1: mlx5e_netdev_init_profile:6214:(pid 37199): mlx5e_priv_init failed, err=-12 mlx5_core 0012:03:00.1 gpu3rdma1: mlx5e_netdev_change_profile: failed to rollback to orig profile, -12
$ devlink dev reload pci/0000:00:03.0 ==> oops
BUG: kernel NULL pointer dereference, address: 0000000000000370 PGD 0 P4D 0 Oops: Oops: 0000 [#1] SMP NOPTI CPU: 15 UID: 0 PID: 520 Comm: devlink Not tainted 6.18.0-rc5+ #115 PREEMPT(voluntary) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-2.fc40 04/01/2014 RIP: 0010:mlx5e_dcbnl_dscp_app+0x23/0x100 RSP: 0018:ffffc9000083f8b8 EFLAGS: 00010286 RAX: ffff8881126fc380 RBX: ffff8881015ac400 RCX: ffffffff826ffc45 RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff8881035109c0 RBP: ffff8881035109c0 R08: ffff888101e3e838 R09: ffff888100264e10 R10: ffffc9000083f898 R11: ffffc9000083f8a0 R12: ffff888101b921a0 R13: ffff888101b921a0 R14: ffff8881015ac9a0 R15: ffff8881015ac400 FS: 00007f789a3c8740(0000) GS:ffff88856aa59000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000370 CR3: 000000010b6c0001 CR4: 0000000000370ef0 Call Trace: <TASK> mlx5e_remove+0x57/0x110 device_release_driver_internal+0x19c/0x200 bus_remove_device+0xc6/0x130 device_del+0x160/0x3d0 ? devl_param_driverinit_value_get+0x2d/0x90 mlx5_detach_device+0x89/0xe0 mlx5_unload_one_devl_locked+0x3a/0x70 mlx5_devlink_reload_down+0xc8/0x220 devlink_reload+0x7d/0x260 devlink_nl_reload_doit+0x45b/0x5a0 genl_family_rcv_msg_doit+0xe8/0x140
Which versions are affected by CVE-2026-23035?
How do I fix CVE-2026-23035?
Apply the vendor's patch.
Is CVE-2026-23035 being exploited?
There is no known exploitation of CVE-2026-23035 in the wild and no public exploit code.
Sources
Also known as AZL-77232, BELL-CVE-2026-23035, DEBIAN-CVE-2026-23035, GHSA-5wr5-mxmx-fvmr, ROOT-OS-DEBIAN-12-CVE-2026-23035, ROOT-OS-DEBIAN-13-CVE-2026-23035 and 3 more.