CVE-2023-54137In the Linux kernel, the following vulnerability has been resolved: vfio/type1: fix cap_migration information leak Fix an information leak where an uninitialized hole in struct vfio_iommu_type1_info_…

In the Linux kernel, the following vulnerability has been resolved: vfio/type1: fix cap_migration information leak Fix an information leak where an uninitialized hole in struct vfio_iommu_type1_info_cap_migration on the stack is exposed to userspace. The definition of struct vfio_iommu_type1_info_cap_migration contains a hole as shown in this pahole(1) output: struct vfio_iommu_type1_info_cap_migration { struct vfio_info_cap_header header; /* 0 8 */ __u32 flags; /* 8 4 */ /* XXX 4 bytes hole, try to pack */ __u64 pgsize_bitmap; /* 16 8 */ __u64 max_dirty_bitmap_size; /* 24 8 */ /* size: 32, cachelines: 1, members: 4 */ /* sum members: 28, holes: 1, sum holes: 4 */ /* last cacheline: 32 bytes */ }; The cap_mig variable is filled in without initializing the hole: static int vfio_iommu_migration_build_caps(struct vfio_iommu *iommu, struct vfio_info_cap *caps) { struct vfio_iommu_type1_info_cap_migration cap_mig; cap_mig.header.id = VFIO_IOMMU_TYPE1_INFO_CAP_MIGRATION; cap_mig.header.version = 1; cap_mig.flags = 0; /* support minimum pgsize */ cap_mig.pgsize_bitmap = (size_t)1 << __ffs(iommu->pgsize_bitmap); cap_mig.max_dirty_bitmap_size = DIRTY_BITMAP_SIZE_MAX; return vfio_info_add_capability(caps, &cap_mig.header, sizeof(cap_mig)); } The structure is then copied to a temporary location on the heap. At this point it's already too late and ioctl(VFIO_IOMMU_GET_INFO) copies it to userspace later: int vfio_info_add_capability(struct vfio_info_cap *caps, struct vfio_info_cap_header *cap, size_t size) { struct vfio_info_cap_header *header; header = vfio_info_cap_add(caps, size, cap->id, cap->version); if (IS_ERR(header)) return PTR_ERR(header); memcpy(header + 1, cap + 1, size - sizeof(*header)); return 0; } This issue was found by code inspection.

CVSS

Not yet scored

Weakness (CWE)

Not given

Known exploited

Not in CISA's KEV catalog

EPSS (exploitation in the next 30 days)

Not loaded for this CVE

Assigned by

Not given

NVD analysis

Deferred

Record last updated

Jun 17, 2026

First seen by InfoSec Signals

Oct 9, 2026

The CVE record on cve.org · NVD's entry

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