Linux Kernel vhost subsystem Vulnerability Rated 7.1 CVSS

Status: UPDATED  |  Advisory ID: CVE-2026-74713

Key Details

Affected Products, Subsystems & Sectors

What to Know

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. (NVD)

What to Do

Monitor Linux's web page for any future patch releases.

References