Linux Kernel up to 7.2.4 f2fs __clone_blkaddrs input validation

Summaryinfo

A vulnerability was found in Linux Kernel up to 7.2.4 and classified as very critical. The impacted element is the function __clone_blkaddrs of the component f2fs. The manipulation results in input validation. This vulnerability is cataloged as CVE-2026-89840. The attack may be launched remotely. There is no exploit available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 7.2.4. It has been classified as very critical. Affected is the function __clone_blkaddrs of the component f2fs. The manipulation with an unknown input leads to a input validation vulnerability. CWE is classifying the issue as CWE-20. The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: f2fs: validate MOVE_RANGE destination size F2FS_IOC_MOVE_RANGE checks the source range, but not the destination end before updating i_size. A source hole can expose this: __clone_blkaddrs() skips NULL_ADDR entries and returns success, so the caller can still extend the destination inode with unchecked pos_out + len. Reject destination overflow and use inode_newsize_ok() before extending the destination inode.

The advisory is available at git.kernel.org. This vulnerability is traded as CVE-2026-89840 since 09/11/2026. The exploitability is told to be easy. It is possible to launch the attack 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 09/16/2026).

Upgrading to version 7.2.5 or 7.3-rc1 eliminates this vulnerability. Applying the patch dcae1eeda53149f219dd6af93b3083b7271c1c63/e533889fc26aea0cd83c90327063f272061dd820 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

License

• open-source

Website

• Vendor: https://www.kernel.org/

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