A type mismatch vulnerability was found in QEMU's vhost inflight migration VMState handling. The destination buffer size is stored as a uint64_t but read by the VMS_VBUFFER load path as a signed int32_t. On little-endian hosts, a crafted incoming migration state with bit 31 set causes the value to be interpreted as negative and then implicitly converted to a very large size_t, leading qemu_get_buffer() to copy migration-stream data beyond the bounds of the mmap-backed inflight region.

This can result in a crash of the QEMU process or memory corruption. Exploitation requires control of the migration producer or write access to the migration channel, combined with a destination configured to use vhost inflight migration.

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Fixes

Solution

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Workaround

If vhost inflight migration is not required, it can be disabled by omitting the inflight parameter from the vhost-user device configuration. This prevents the vulnerable VMState deserialization path from being reached on the destination. Environments that require vhost inflight migration for live migration of vhost-user devices cannot use this mitigation and should prioritize applying the fix.

History

Mon, 10 Aug 2026 21:30:00 +0000

Type Values Removed Values Added
Description A type mismatch vulnerability was found in QEMU's vhost inflight migration VMState handling. The destination buffer size is stored as a uint64_t but read by the VMS_VBUFFER load path as a signed int32_t. On little-endian hosts, a crafted incoming migration state with bit 31 set causes the value to be interpreted as negative and then implicitly converted to a very large size_t, leading qemu_get_buffer() to copy migration-stream data beyond the bounds of the mmap-backed inflight region. This can result in a crash of the QEMU process or memory corruption. Exploitation requires control of the migration producer or write access to the migration channel, combined with a destination configured to use vhost inflight migration.
Title Qemu-kvm: vhost inflight migration vmstate integer type mismatch causes out-of-bounds access
First Time appeared Redhat
Redhat enterprise Linux
Redhat enterprise Linux Nvidia
Redhat openshift
Weaknesses CWE-681
CPEs cpe:/a:redhat:enterprise_linux_nvidia:
cpe:/a:redhat:openshift:4
cpe:/o:redhat:enterprise_linux:10
cpe:/o:redhat:enterprise_linux:6
cpe:/o:redhat:enterprise_linux:7
cpe:/o:redhat:enterprise_linux:8
cpe:/o:redhat:enterprise_linux:9
Vendors & Products Redhat
Redhat enterprise Linux
Redhat enterprise Linux Nvidia
Redhat openshift
References
Metrics cvssV3_1

{'score': 4.4, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H'}


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cve-icon MITRE

Status: PUBLISHED

Assigner: redhat

Published:

Updated: 2026-08-10T21:22:29.414Z

Reserved: 2026-04-16T11:09:18.538Z

Link: CVE-2026-6426

cve-icon Vulnrichment

No data.

cve-icon NVD

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cve-icon Redhat

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cve-icon OpenCVE Enrichment

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Weaknesses