Linux Kernel up to 6.18.13/6.19.3 netdev_trylock deadlock

Summaryinfo

A vulnerability, which was classified as critical, has been found in Linux Kernel up to 6.18.13/6.19.3. The impacted element is the function netdev_trylock. Performing a manipulation results in deadlock. This vulnerability is reported as CVE-2026-45907. No exploit exists. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as critical, was found in Linux Kernel up to 6.18.13/6.19.3. This affects the function netdev_trylock. The manipulation with an unknown input leads to a deadlock vulnerability. CWE is classifying the issue as CWE-833. The product contains multiple threads or executable segments that are waiting for each other to release a necessary lock, resulting in deadlock. This is going to have an impact on availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: net/mlx5e: Fix deadlocks between devlink and netdev instance locks In the mentioned "Fixes" commit, various work tasks triggering devlink health reporter recovery were switched to use netdev_trylock to protect against concurrent tear down of the channels being recovered. But this had the side effect of introducing potential deadlocks because of incorrect lock ordering. The correct lock order is described by the init flow: probe_one -> mlx5_init_one (acquires devlink lock) -> mlx5_init_one_devl_locked -> mlx5_register_device -> mlx5_rescan_drivers_locked -...-> mlx5e_probe -> _mlx5e_probe -> register_netdev (acquires rtnl lock) -> register_netdevice (acquires netdev lock) => devlink lock -> rtnl lock -> netdev lock. But in the current recovery flow, the order is wrong: mlx5e_tx_err_cqe_work (acquires netdev lock) -> mlx5e_reporter_tx_err_cqe -> mlx5e_health_report -> devlink_health_report (acquires devlink lock => boom!) -> devlink_health_reporter_recover -> mlx5e_tx_reporter_recover -> mlx5e_tx_reporter_recover_from_ctx -> mlx5e_tx_reporter_err_cqe_recover The same pattern exists in: mlx5e_reporter_rx_timeout mlx5e_reporter_tx_ptpsq_unhealthy mlx5e_reporter_tx_timeout Fix these by moving the netdev_trylock calls from the work handlers lower in the call stack, in the respective recovery functions, where they are actually necessary.

It is possible to read the advisory at git.kernel.org. This vulnerability is uniquely identified as CVE-2026-45907 since 05/13/2026. The exploitability is told to be difficult. Technical details of the vulnerability are known, but there is no available exploit.

Upgrading to version 6.18.14 or 6.19.4 eliminates this vulnerability. Applying the patch 4329514c61abefe4961541b128c549b017bab5ad/63f9d5fb4d8040077df801ca3270e2f02d55e0d9/83ac0304a2d77519dae1e54c9713cbe1aedf19c9 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at CERT Bund (WID-SEC-2026-1700). Be aware that VulDB is the high quality source for vulnerability data.

Affected

• Google Container-Optimized OS
• Debian Linux
• Red Hat Enterprise Linux
• Ubuntu Linux
• SUSE Linux
• Oracle Linux
• SUSE openSUSE
• RESF Rocky Linux
• Open Source Linux Kernel

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.18.0
• 6.18.1
• 6.18.2
• 6.18.3
• 6.18.4
• 6.18.5
• 6.18.6
• 6.18.7
• 6.18.8
• 6.18.9
• 6.18.10
• 6.18.11
• 6.18.12
• 6.18.13
• 6.19.0
• 6.19.1
• 6.19.2
• 6.19.3

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

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CPE 2.2info

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Entryinfo

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