Summaryinfo

A vulnerability classified as critical has been found in Linux Kernel up to 6.11.2. This affects the function memfd_alloc_folio of the component hugetlb. The manipulation leads to reference count. This vulnerability is uniquely identified as CVE-2024-49964. There is no exploit available. It is recommended to upgrade the affected component. If you want to get best quality of vulnerability data, you may have to visit VulDB.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.11.2. It has been rated as critical. Affected by this issue is the function memfd_alloc_folio of the component hugetlb. The manipulation with an unknown input leads to a reference count vulnerability. Using CWE to declare the problem leads to CWE-911. The product uses a reference count to manage a resource, but it does not update or incorrectly updates the reference count. Impacted is availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: mm/hugetlb: fix memfd_pin_folios free_huge_pages leak memfd_pin_folios followed by unpin_folios fails to restore free_huge_pages if the pages were not already faulted in, because the folio refcount for pages created by memfd_alloc_folio never goes to 0. memfd_pin_folios needs another folio_put to undo the folio_try_get below: memfd_alloc_folio() alloc_hugetlb_folio_nodemask() dequeue_hugetlb_folio_nodemask() dequeue_hugetlb_folio_node_exact() folio_ref_unfreeze(folio, 1); ; adds 1 refcount folio_try_get() ; adds 1 refcount hugetlb_add_to_page_cache() ; adds 512 refcount (on x86) With the fix, after memfd_pin_folios + unpin_folios, the refcount for the (unfaulted) page is 512, which is correct, as the refcount for a faulted unpinned page is 513.

The advisory is available at git.kernel.org. This vulnerability is handled as CVE-2024-49964 since 10/21/2024. Technical details are known, but there is no available exploit.

The vulnerability scanner Nessus provides a plugin with the ID 216493 (Ubuntu 24.10 : Linux kernel vulnerabilities (USN-7276-1)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.11.3 eliminates this vulnerability. Applying the patch 59e081ff2e91/c56b6f3d801d 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 vulnerability database at Tenable (216493). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.11.0
• 6.11.1
• 6.11.2

License

• open-source

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CPE 2.2info

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