Linux Kernel up to 7.1.5/7.2-rc4 cifs allocation of resources

Summaryinfo

A vulnerability identified as critical has been detected in Linux Kernel up to 7.1.5/7.2-rc4. Impacted is the function cifs_close_deferred_file/cifs_close_all_deferred_files/cifs_close_deferred_file_under_dentry of the component cifs. Performing a manipulation results in allocation of resources. This vulnerability is identified as CVE-2026-68312. The attack is only possible with local access. There is not any exploit available.

Detailsinfo

A vulnerability classified as critical has been found in Linux Kernel up to 7.1.5/7.2-rc4. This affects the function cifs_close_deferred_file/cifs_close_all_deferred_files/cifs_close_deferred_file_under_dentry of the component cifs. The manipulation with an unknown input leads to a allocation of resources vulnerability. CWE is classifying the issue as CWE-770. The product allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor. This is going to have an impact on availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: cifs: fix cifsFileInfo leak on kmalloc failure in deferred close drain paths In cifs_close_deferred_file(), cifs_close_all_deferred_files(), and cifs_close_deferred_file_under_dentry(), when a pending deferred close is cancelled via cancel_delayed_work(), the subsequent kmalloc_obj() to add the file to the local processing list may fail under memory pressure. The loop breaks immediately, but the cancelled work is no longer pending (it would have called _cifsFileInfo_put()), and the cfile is never added to file_head for processing. The cifsFileInfo reference and the open server handle both leak. Fix by saving the cfile that failed allocation in a local variable, breaking as before, and calling _cifsFileInfo_put() on it after releasing the lock. Any files later in the iteration are unaffected since their deferred work is still pending and will fire normally.

It is possible to read the advisory at git.kernel.org. This vulnerability is uniquely identified as CVE-2026-68312 since 07/30/2026. The exploitability is told to be easy. Attacking locally is a requirement. Technical details of the vulnerability are known, but there is no available exploit.

Upgrading to version 7.1.6 or 7.2-rc5 eliminates this vulnerability. Applying the patch 32390b3f06f26e366cfb27dbac4bc0196c321535/c2f2e83e3bbc5483730fd4ee903182761f1ae50f is able to eliminate this problem.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 7.1.0
• 7.1.1
• 7.1.2
• 7.1.3
• 7.1.4
• 7.1.5
• 7.2-rc1
• 7.2-rc2
• 7.2-rc3
• 7.2-rc4

License

• open-source

Website

• Vendor: https://www.kernel.org/

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