Linux Kernel up to 6.12.44/6.16.4/6.17-rc3 buffer overflow

Summaryinfo

A vulnerability has been found in Linux Kernel up to 6.12.44/6.16.4/6.17-rc3 and classified as critical. This affects an unknown part. The manipulation leads to buffer overflow. This vulnerability is referenced as CVE-2025-39815. No exploit is available. The affected component should be upgraded.

Detailsinfo

A vulnerability, which was classified as critical, has been found in Linux Kernel up to 6.12.44/6.16.4/6.17-rc3. This issue affects an unknown part. The manipulation with an unknown input leads to a buffer overflow vulnerability. Using CWE to declare the problem leads to CWE-120. The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: RISC-V: KVM: fix stack overrun when loading vlenb The userspace load can put up to 2048 bits into an xlen bit stack buffer. We want only xlen bits, so check the size beforehand.

The advisory is shared at git.kernel.org. The identification of this vulnerability is CVE-2025-39815 since 04/16/2025. The exploitation is known to be easy. Neither technical details nor an exploit are publicly available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 12/27/2025).

The vulnerability scanner Nessus provides a plugin with the ID 265290 (Linux Distros Unpatched Vulnerability : CVE-2025-39815), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.12.45, 6.16.5 or 6.17-rc4 eliminates this vulnerability. Applying the patch c76bf8359188a11f8fd790e5bbd6077894a245cc/6d28659b692a0212f360f8bd8a58712b339f9aac/799766208f09f95677a9ab111b93872d414fbad7 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 (265290) and CERT Bund (WID-SEC-2025-2077). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Affected

• 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
• Dell Secure Connect Gateway

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 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
• 6.16.0
• 6.16.1
• 6.16.2
• 6.16.3
• 6.16.4
• 6.17-rc1
• 6.17-rc2
• 6.17-rc3

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

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CPE 2.2info

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Exploitinginfo

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Entryinfo

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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