Bug 2429074 (CVE-2025-68779)

Summary: CVE-2025-68779 kernel: net/mlx5e: Avoid unregistering PSP twice
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
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Priority: medium    
Version: unspecifiedKeywords: Security
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OS: Linux   
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A use-after-free vulnerability was found in the Mellanox mlx5 Ethernet driver in the Linux kernel. The PSP (Platform Security Processor) component is unregistered twice during device removal - once in _mlx5e_remove() and again in mlx5e_nic_cleanup(). This double unregistration causes a refcount underflow, triggering a use-after-free condition.
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Description OSIDB Bzimport 2026-01-13 16:04:52 UTC 
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.
Comment 1 Jon Moroney 2026-01-15 01:12:20 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026011300-CVE-2025-68779-726e@gregkh/T