Bug 2464378 (CVE-2026-43013)

Summary: CVE-2026-43013 kernel: net/mlx5: lag: Check for LAG device before creating debugfs
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
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Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's `net/mlx5` driver. An error in the `__mlx5_lag_dev_add_mdev()` function can lead to the creation of debugfs entries without a valid LAG (Link Aggregation Group) context. This exposes interfaces that rely on a valid pointer, potentially leading to a NULL pointer dereference if accessed. Such a dereference could result in a system crash, causing a denial of service (DoS).
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Description OSIDB Bzimport 2026-05-01 15:03:19 UTC 
In the Linux kernel, the following vulnerability has been resolved:

net/mlx5: lag: Check for LAG device before creating debugfs

__mlx5_lag_dev_add_mdev() may return 0 (success) even when an error
occurs that is handled gracefully. Consequently, the initialization
flow proceeds to call mlx5_ldev_add_debugfs() even when there is no
valid LAG context.

mlx5_ldev_add_debugfs() blindly created the debugfs directory and
attributes. This exposed interfaces (like the members file) that rely on
a valid ldev pointer, leading to potential NULL pointer dereferences if
accessed when ldev is NULL.

Add a check to verify that mlx5_lag_dev(dev) returns a valid pointer
before attempting to create the debugfs entries.
Comment 1 Keith Grant 2026-05-01 16:24:13 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026050155-CVE-2026-43013-be27@gregkh/T