CVE-2026-23067

Technical Description

In the Linux kernel, the following vulnerability has been resolved:

iommu/io-pgtable-arm: fix size_t signedness bug in unmap path

__arm_lpae_unmap() returns size_t but was returning -ENOENT (negative

error code) when encountering an unmapped PTE. Since size_t is unsigned,

-ENOENT (typically -2) becomes a huge positive value (0xFFFFFFFFFFFFFFFE

on 64-bit systems).

This corrupted value propagates through the call chain:

__arm_lpae_unmap() returns -ENOENT as size_t

-> arm_lpae_unmap_pages() returns it

-> __iommu_unmap() adds it to iova address

-> iommu_pgsize() triggers BUG_ON due to corrupted iova

This can cause IOVA address overflow in __iommu_unmap() loop and

trigger BUG_ON in iommu_pgsize() from invalid address alignment.

Fix by returning 0 instead of -ENOENT. The WARN_ON already signals

the error condition, and returning 0 (meaning "nothing unmapped")

is the correct semantic for size_t return type. This matches the

behavior of other io-pgtable implementations (io-pgtable

Remediation

Check the references section for vendor advisories and patches from linux. Update linux_kernel to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

Affected Products

References