Linux Kernel up to 7.1.4 RDMA/nldev rdma_restrack_sync locking

Summaryinfo

A vulnerability was found in Linux Kernel up to 7.1.4. It has been classified as very critical. This vulnerability affects the function rdma_restrack_sync of the component RDMA/nldev. This manipulation causes locking. This vulnerability appears as CVE-2026-74334. The attack may be initiated remotely. There is no available exploit.

Detailsinfo

A vulnerability was found in Linux Kernel up to 7.1.4. It has been declared as very critical. Affected by this vulnerability is the function rdma_restrack_sync of the component RDMA/nldev. The manipulation with an unknown input leads to a locking vulnerability. The CWE definition for the vulnerability is CWE-667. The product does not properly acquire or release a lock on a resource, leading to unexpected resource state changes and behaviors. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: RDMA/nldev: Fix locking when accessing mr->pd Sashiko points out that, due to rereg_mr, the PD is actually variable and all the touches in nldev are racy. Use mr->device instead of mr->pd->device. Getting the PD restrack ID is more tricky. To avoid disturbing all the happy paths, add an rdma_restrack_sync() operation which is sort of like flush_workqueue() or synchronize_irq(): after it returns, all the old nldev touches to the mr are gone and everything sees the new PD. This makes it safe to reach into the PD pointer.

It is possible to read the advisory at git.kernel.org. This vulnerability is known as CVE-2026-74334 since 08/15/2026. The exploitation appears to be easy. The attack can be launched remotely. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 08/15/2026).

Upgrading to version 7.1.5 or 7.2-rc1 eliminates this vulnerability. Applying the patch 1a132ee4e655288d9a0937ea5109a0d038431ae9/50d5c02ab8e62325548bd3a6e6b758a9dcd6e7c3 is able to eliminate this problem.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 7.1.0
• 7.1.1
• 7.1.2
• 7.1.3
• 7.1.4

License

• open-source

Website

• Vendor: https://www.kernel.org/

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