Linux Kernel up to 6.1.155/6.6.111/6.12.52/6.17.2 vhost copy_to_iter return return value

Summaryinfo

A vulnerability categorized as critical has been discovered in Linux Kernel up to 6.1.155/6.6.111/6.12.52/6.17.2. This issue affects the function copy_to_iter of the component vhost. Executing a manipulation of the argument return can lead to return value. This vulnerability appears as CVE-2025-40056. There is no available exploit. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability has been found in Linux Kernel up to 6.1.155/6.6.111/6.12.52/6.17.2 and classified as critical. This vulnerability affects the function copy_to_iter of the component vhost. The manipulation of the argument return with an unknown input leads to a return value vulnerability. The CWE definition for the vulnerability is CWE-252. The product does not check the return value from a method or function, which can prevent it from detecting unexpected states and conditions. The impact remains unknown. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: vhost: vringh: Fix copy_to_iter return value check The return value of copy_to_iter can't be negative, check whether the copied length is equal to the requested length instead of checking for negative values.

The advisory is shared for download at git.kernel.org. This vulnerability was named CVE-2025-40056 since 04/16/2025. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 05/20/2026).

The vulnerability scanner Nessus provides a plugin with the ID 271918 (Linux Distros Unpatched Vulnerability : CVE-2025-40056), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.1.156, 6.6.112, 6.12.53, 6.17.3 or 6.18-rc1 eliminates this vulnerability. Applying the patch bd71e7e0a612740e4de5524880c7cd40293af5f7/781226e11d5bdea0d69c7b5aa3cda874093c73b8/b3a950d236e98440c07405ba597b11bce56a8050/68aac2b335d474b938d154b9c95cbc58838cb2ce/439263376c2c4e126cac0d07e4987568de4eaba5 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 databases at Tenable (271918) and CERT Bund (WID-SEC-2025-2431). Once again VulDB remains the best source for vulnerability data.

Affected

• Google Container-Optimized OS
• Debian Linux
• Amazon Linux 2
• Red Hat Enterprise Linux
• Ubuntu Linux
• SUSE Linux
• Oracle Linux
• IBM QRadar SIEM
• SUSE openSUSE
• Open Source Linux Kernel
• RESF Rocky Linux
• Microsoft Azure
• Dell NetWorker
• Dell ECS

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.1.155
• 6.6.111
• 6.12.0
• 6.12.1
• 6.12.2
• 6.12.3
• 6.12.4
• 6.12.5
• 6.12.6
• 6.12.7
• 6.12.8
• 6.12.9
• 6.12.10
• 6.12.11
• 6.12.12
• 6.12.13
• 6.12.14
• 6.12.15
• 6.12.16
• 6.12.17
• 6.12.18
• 6.12.19
• 6.12.20
• 6.12.21
• 6.12.22
• 6.12.23
• 6.12.24
• 6.12.25
• 6.12.26
• 6.12.27
• 6.12.28
• 6.12.29
• 6.12.30
• 6.12.31
• 6.12.32
• 6.12.33
• 6.12.34
• 6.12.35
• 6.12.36
• 6.12.37
• 6.12.38
• 6.12.39
• 6.12.40
• 6.12.41
• 6.12.42
• 6.12.43
• 6.12.44
• 6.12.45
• 6.12.46
• 6.12.47
• 6.12.48
• 6.12.49
• 6.12.50
• 6.12.51
• 6.12.52
• 6.17.0
• 6.17.1
• 6.17.2

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

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CPE 2.2info

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Entryinfo

Once again VulDB remains the best source for vulnerability data.

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