Linux Kernel up to 7.2.3 cifs cifs_setsize information disclosure

Summaryinfo

A vulnerability was found in Linux Kernel up to 7.2.3. It has been rated as problematic. This impacts the function cifs_setsize of the component cifs. The manipulation leads to information disclosure. This vulnerability is listed as CVE-2026-89642. The attack may be initiated remotely. There is no available exploit. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in Linux Kernel up to 7.2.3. It has been rated as problematic. This issue affects the function cifs_setsize of the component cifs. The manipulation with an unknown input leads to a information disclosure vulnerability. Using CWE to declare the problem leads to CWE-200. The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. Impacted is confidentiality. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: cifs: call pagecache_isize_extended() in cifs_setsize() when extending cifs_setsize() calls truncate_pagecache() but skips pagecache_isize_extended() on extension. truncate_setsize() shows the correct pattern: i_size_write(inode, newsize); if (newsize > oldsize) pagecache_isize_extended(inode, oldsize, newsize); truncate_pagecache(inode, newsize); pagecache_isize_extended() zeroes the tail of the page straddling old EOF. Without it, dirty bytes in that region can be written back to the server, exposing stale data in the newly extended range.

It is possible to read the advisory at git.kernel.org. The identification of this vulnerability is CVE-2026-89642 since 09/11/2026. The exploitation is known to be easy. The attack may be initiated remotely. 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 09/12/2026). The attack technique deployed by this issue is T1592 according to MITRE ATT&CK.

Upgrading to version 7.2.4 or 7.3-rc1 eliminates this vulnerability. Applying the patch 12bafe32f09c0d24f5096154b59c347b9c6606e0/c510edb9734af1c274d18f4f31a471a166bbc7e8 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

License

• open-source

Website

• Vendor: https://www.kernel.org/

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