Linux Kernel up to 7.1.8 vhost_iotlb vhost.c vhost_iotlb_add_range_ctx allocation of resources

Summaryinfo

A vulnerability labeled as very critical has been found in Linux Kernel up to 7.1.8. This vulnerability affects the function vhost_iotlb_add_range_ctx of the file vhost.c of the component vhost_iotlb. Executing a manipulation can lead to allocation of resources. The identification of this vulnerability is CVE-2026-74713. The attack may be launched remotely. There is no exploit available.

Detailsinfo

A vulnerability has been found in Linux Kernel up to 7.1.8 and classified as very critical. This vulnerability affects the function vhost_iotlb_add_range_ctx of the file vhost.c of the component vhost_iotlb. 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 confidentiality, integrity, and availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: vhost_iotlb: bound map allocation in add_range vhost_iotlb_add_range_ctx() only retires an old entry when the table has a non-zero limit, has exactly reached that limit and has VHOST_IOTLB_FLAG_RETIRE set. Non-retiring tables can keep allocating entries after reaching their configured limit. Existing vhost devices allocate their IOTLB with max_iotlb_entries from vhost.c, which defaults to 2048 and is tunable by module parameter. Use the caller-provided limit at the allocation point instead of adding a separate default in the common IOTLB helper, and reject non-positive values in vhost paths that can report an error. Other vhost IOTLB users should not create zero-limit tables when entries can be populated from userspace or guest-controlled requests. Add caller-side max_iotlb_entries parameters for mlx5 vDPA, VDUSE and vhost-vDPA. Reject non-positive VDUSE and vhost-vDPA values, and require at least two entries for vdpa_sim and mlx5 vDPA paths that install full-range mappings, since those mappings are split into two IOTLB entries. Handle full-range mappings in the common helper by checking that the IOTLB can hold both split entries before inserting the first half. This avoids returning an error after leaving a half mapping behind. When the table is full, keep the existing retire behavior for retiring tables and return -ENOSPC for non-retiring tables. Reuse the retired map node instead of freeing it and allocating a replacement, so a stream of IOTLB updates cannot keep forcing GFP_ATOMIC allocations after the table has reached its limit. If a zero-limit IOTLB still reaches the common helper, treat it as a configuration error and return -EINVAL. I found this bug myself, though the patch was written with AI assistance.

The advisory is available at git.kernel.org. This vulnerability was named CVE-2026-74713 since 08/15/2026. The exploitation appears to be easy. The attack can be initiated remotely. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 08/22/2026). This vulnerability is assigned to T1499 by the MITRE ATT&CK project.

Upgrading to version 7.1.9 eliminates this vulnerability. Applying the patch ae128dd19040ee06a4f8143c7ced4d18080d7a9a/1ed35ac7f3fe2b4396bdd29ac3a7f0ebc0829e94 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
• 7.1.6
• 7.1.7
• 7.1.8

License

• open-source

Website

• Vendor: https://www.kernel.org/

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