CVE-2026-6426Qemu-kvm: vhost inflight migration vmstate integer type mismatch causes out-of-bounds access
- 4.4MediumCVSS base score
- 0.39%Exploitation in 30 daysEPSS · top 66% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
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.
Timeline
ID reserved
By redhat
- 4 months later
· 4 months later
Published
- 3 months later
· 3 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| redhatCNA (assigner) | 3.1 | Medium4.4 | CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H |
| NVDNVD · Awaiting Analysis | 3.1 | Medium4.4 | CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 0.39% · top 66% of all CVEs (14 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 4.4.
Affected products
Red Hat · Red Hat Enterprise Linux 10
All versions: affected
Red Hat · Red Hat Enterprise Linux 6
All versions: affected
Red Hat · Red Hat Enterprise Linux 7
All versions: affected
Red Hat · Red Hat Enterprise Linux 7
All versions: affected
Red Hat · Red Hat Enterprise Linux 8
All versions: affected
Red Hat · Red Hat Enterprise Linux 9
All versions: affected
Red Hat · Red Hat Enterprise Linux for NVIDIA 26
All versions: unknown
Red Hat · Red Hat OpenShift Container Platform 4
All versions: affected
Red Hat · Red Hat OpenShift Container Platform 4
All versions: affected
Red Hat · Red Hat OpenShift Container Platform 5
All versions: affected
What to do
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.
References
References2
- https://access.redhat.com/security/cve/CVE-2026-6426 (opens in a new tab)vdb-entryx_refsource_REDHAT
- RHBZ#2513498 (opens in a new tab)issue-trackingx_refsource_REDHAT
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-55840 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-6426)Record last updated .