Linux Kernel up to 7.2.5 Dax Fsdev dax/fsdev devm_memremap_pages vmemmap_shift memory corruption

Summaryinfo

A vulnerability was found in Linux Kernel up to 7.2.5. It has been declared as very critical. The affected element is the function devm_memremap_pages of the file dax/fsdev of the component Dax Fsdev. Executing a manipulation of the argument vmemmap_shift can lead to memory corruption. This vulnerability is tracked as CVE-2026-93076. The attack can be launched remotely. No exploit exists. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability has been found in Linux Kernel up to 7.2.5 and classified as very critical. This vulnerability affects the function devm_memremap_pages of the file dax/fsdev of the component Dax Fsdev. The manipulation of the argument vmemmap_shift with an unknown input leads to a memory corruption vulnerability. The CWE definition for the vulnerability is 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. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: dax/fsdev: clear vmemmap_shift when binding static pgmap Clear pgmap->vmemmap_shift for static DAX devices. When rebinding a static device from device_dax (which may set vmemmap_shift based on alignment) to fsdev_dax, the stale vmemmap_shift persists on the shared pgmap. Explicitly zero it before devm_memremap_pages() so the vmemmap is built for order-0 folios as fsdev requires.

The advisory is available at git.kernel.org. This vulnerability was named CVE-2026-93076 since 09/17/2026. The exploitation appears to be easy. The attack can be initiated remotely. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $5k-$25k at the moment (estimation calculated on 09/17/2026).

Upgrading to version 7.2.6 or 7.3-rc1 eliminates this vulnerability. Applying the patch d298a0513aaf7d48f2a9f4a90041de910750cfcf/e0239229931faf9ca3367e3befcf16f77b2cd45b is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 7.2.0
• 7.2.1
• 7.2.2
• 7.2.3
• 7.2.4
• 7.2.5

License

• open-source

Website

• Vendor: https://www.kernel.org/

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