Linux Kernel up to 6.18.3 KVM gmap_helper_zap_one_page memory corruption

Summaryinfo

A vulnerability, which was classified as critical, was found in Linux Kernel up to 6.18.3. This vulnerability affects the function gmap_helper_zap_one_page of the component KVM. Such manipulation leads to memory corruption. This vulnerability is traded as CVE-2025-71155. There is no exploit available. You should upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.18.3 and classified as critical. Affected by this issue is the function gmap_helper_zap_one_page of the component KVM. The manipulation with an unknown input leads to a memory corruption vulnerability. Using CWE to declare the problem leads to CWE-119. The product performs operations on a memory buffer, but it can read from or write to a memory location that is outside of the intended boundary of the buffer. Impacted is confidentiality, integrity, and availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: KVM: s390: Fix gmap_helper_zap_one_page() again A few checks were missing in gmap_helper_zap_one_page(), which can lead to memory corruption in the guest under specific circumstances. Add the missing checks.

The advisory is available at git.kernel.org. This vulnerability is handled as CVE-2025-71155 since 01/13/2026. The exploitation is known to be easy. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 05/17/2026).

The vulnerability scanner Nessus provides a plugin with the ID 296407 (Linux Distros Unpatched Vulnerability : CVE-2025-71155), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.18.4 or 6.19-rc1 eliminates this vulnerability. Applying the patch 2af2abbcbf8573100288e8f8aea2dab8a2a0ceb7/2f393c228cc519ddf19b8c6c05bf15723241aa96 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 (296407) and CERT Bund (WID-SEC-2026-0215). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Affected

• Debian Linux
• Amazon Linux 2
• Red Hat Enterprise Linux
• Ubuntu Linux
• SUSE Linux
• Oracle Linux
• IBM QRadar SIEM
• SUSE openSUSE
• RESF Rocky Linux
• NetApp ActiveIQ Unified Manager
• 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

License

• open-source

Website

• Vendor: https://www.kernel.org/

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Entryinfo

If you want to get best quality of vulnerability data, you may have to visit VulDB.

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