Linux Kernel ntfs get_nr_free_clusters allocation of resources

Summaryinfo

A vulnerability was found in Linux Kernel. It has been rated as critical. The affected element is the function get_nr_free_clusters of the component ntfs. This manipulation causes allocation of resources. The identification of this vulnerability is CVE-2026-72202. It is possible to initiate the attack remotely. There is no exploit available.

Detailsinfo

A vulnerability has been found in Linux Kernel (version unknown) and classified as critical. Affected by this vulnerability is the function get_nr_free_clusters of the component ntfs. The manipulation with an unknown input leads to a allocation of resources vulnerability. The CWE definition for the vulnerability is 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. As an impact it is known to affect availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: ntfs: avoid heap allocation for free-cluster readahead state get_nr_free_clusters() allocates a temporary file_ra_state before it publishes the precomputed free cluster count, sets NVolFreeClusterKnown(), and wakes vol->free_waitq. If that allocation fails, the worker returns without setting the flag or waking waiters, so callers waiting for the free count can block indefinitely. The readahead state is only used synchronously while scanning the bitmap. Keep it on the stack and pass it by address to the readahead helper. This eliminates the early allocation failure path instead of adding a special case that publishes a conservative count and wakes the waitqueue. Zero-initialize the on-stack state because file_ra_state_init() only sets ra_pages and prev_pos. Apply the same treatment to __get_nr_free_mft_records(), which scans the MFT bitmap with the same short-lived readahead state.

The advisory is shared at git.kernel.org. This vulnerability is known as CVE-2026-72202 since 08/09/2026. The exploitation appears to be easy. The attack can be launched remotely. Technical details are known, but no exploit is available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 08/15/2026). MITRE ATT&CK project uses the attack technique T1499 for this issue.

Applying the patch 40ee64e633e5e413f2255bb48c063977d8c86f34 is able to eliminate this problem.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

License

• open-source

Website

• Vendor: https://www.kernel.org/

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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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