CVE-2025-68779 net/mlx5e: Avoid unregistering PSP twice
A double unregister bug in the Linux kernel mlx5e driver causes a use-after-free, potentially leading to system crashes or code execution.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-68779?
CVE-2025-68779 is an use after free vulnerability in Linux, published on 13 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: Avoid unregistering PSP twice
PSP is unregistered twice in: _mlx5e_remove -> mlx5e_psp_unregister mlx5e_nic_cleanup -> mlx5e_psp_unregister
This leads to a refcount underflow in some conditions: ------------[ cut here ]------------ refcount_t: underflow; use-after-free. WARNING: CPU: 2 PID: 1694 at lib/refcount.c:28 refcount_warn_saturate+0xd8/0xe0 [...] mlx5e_psp_unregister+0x26/0x50 [mlx5_core] mlx5e_nic_cleanup+0x26/0x90 [mlx5_core] mlx5e_remove+0xe6/0x1f0 [mlx5_core] auxiliary_bus_remove+0x18/0x30 device_release_driver_internal+0x194/0x1f0 bus_remove_device+0xc6/0x130 device_del+0x159/0x3c0 mlx5_rescan_drivers_locked+0xbc/0x2a0 [mlx5_core] [...]
Do not directly remove psp from the _mlx5e_remove path, the PSP cleanup happens as part of profile cleanup.
Which versions are affected by CVE-2025-68779?
How do I fix CVE-2025-68779?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2025-68779 being exploited?
There is no known exploitation of CVE-2025-68779 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2025-68779, GHSA-7crx-7pfp-hg6j, ROOT-OS-UBUNTU-2204-CVE-2025-68779, ROOT-OS-UBUNTU-2404-CVE-2025-68779, UBUNTU-CVE-2025-68779.