Linux Kernel up to 6.17.2 misc pci_endpoint_test_ioctl buffer under-read

Summaryinfo

A vulnerability, which was classified as critical, has been found in Linux Kernel up to 6.17.2. Affected by this vulnerability is the function pci_endpoint_test_ioctl of the component Misc. The manipulation leads to buffer under-read. This vulnerability is listed as CVE-2025-40117. There is no available exploit. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.17.2 and classified as critical. This issue affects the function pci_endpoint_test_ioctl of the component misc. The manipulation with an unknown input leads to a buffer under-read vulnerability. Using CWE to declare the problem leads to CWE-127. The product reads from a buffer using buffer access mechanisms such as indexes or pointers that reference memory locations prior to the targeted buffer. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: misc: pci_endpoint_test: Fix array underflow in pci_endpoint_test_ioctl() Commit eefb83790a0d ("misc: pci_endpoint_test: Add doorbell test case") added NO_BAR (-1) to the pci_barno enum which, in practical terms, changes the enum from an unsigned int to a signed int. If the user passes a negative number in pci_endpoint_test_ioctl() then it results in an array underflow in pci_endpoint_test_bar().

It is possible to read the advisory at git.kernel.org. The identification of this vulnerability is CVE-2025-40117 since 04/16/2025. 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 02/15/2026).

The vulnerability scanner Nessus provides a plugin with the ID 298897 (Ubuntu 25.10 : Linux kernel vulnerabilities (USN-8029-1)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.17.3 or 6.18-rc1 eliminates this vulnerability. Applying the patch 6df3687922570f753574c40b35e83b26b32292d0/1ad82f9db13d85667366044acdfb02009d576c5a 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 (298897) and CERT Bund (WID-SEC-2025-2579). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Affected

• Google Container-Optimized OS
• Debian Linux
• Amazon Linux 2
• Red Hat Enterprise Linux
• Ubuntu Linux
• SUSE Linux
• Oracle Linux
• SUSE openSUSE
• Open Source Linux Kernel
• RESF Rocky Linux

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.17.0
• 6.17.1
• 6.17.2

License

• open-source

Website

• Vendor: https://www.kernel.org/

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Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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