Medium

CVE-2026-6426 — Qemu-kvm: vhost inflight migration vmstate integer type mismatch causes out-of-bounds access

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.

Published Aug 10, 2026 · Updated Oct 15, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: redhat

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

EPSS 0.4% (30-day exploitation probability)+5
Technical severity (medium)+3

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

0.39%

ahead of 32% of scored CVEs · Oct 15, 2026

Affects

Red Hat

Red Hat Enterprise Linux 10 and 5 more

CVSS base

4.4

Medium · 2 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation

None

none · proof-of-concept · active

Automatable

can an attacker script the kill-chain steps

Technical impact

Partial

partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Red Hat Red Hat Enterprise Linux 10, Red Hat Red Hat Enterprise Linux 6, Red Hat Red Hat Enterprise Linux 7…).
No fix documented in the sources: reduce exposure and monitor the vendor advisory.
Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Red Hat	Red Hat Enterprise Linux 10	versions not specified by the source	Vulnerable	CVE Program (cve.org) e CISA ADP
Red Hat	Red Hat Enterprise Linux 6	versions not specified by the source	Vulnerable	CVE Program (cve.org) e CISA ADP
Red Hat	Red Hat Enterprise Linux 7	versions not specified by the source	Vulnerable	CVE Program (cve.org) e CISA ADP
Red Hat	Red Hat Enterprise Linux 8	versions not specified by the source	Vulnerable	CVE Program (cve.org) e CISA ADP
Red Hat	Red Hat Enterprise Linux 9	versions not specified by the source	Vulnerable	CVE Program (cve.org) e CISA ADP
Red Hat	Red Hat OpenShift Container Platform 4	versions not specified by the source	Vulnerable	CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector

Network

Attack complexity

High

Privileges required

High

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Scored by
4.4	CVSS 3.1	Medium	0.7	3.6	secalert@redhat.com via NIST National Vulnerability Database
4.4	CVSS 3.1	Medium	—	—	redhat via CVE Program (cve.org) e CISA ADP

CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H (score shown at the top: secalert@redhat.com)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-681

Other CVEs with this weakness →

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).

web/proxy/WAF logsnetwork IDS/IPS

Timeline

What happened to this CVE, newest first.

2026
Affected products added · red hat/red hat enterprise linux 10, red hat/red hat enterprise linux 6, red hat/red hat enterprise linux 7, red hat/red
Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
SSVC assessment updated
Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 15, 2026
CVSS changed · 4.4
Oct 15, 2026 · NIST National Vulnerability Database
Source status changed · → Awaiting Analysis
Oct 15, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 15, 2026 · NIST National Vulnerability Database
CVE published
Aug 10, 2026 · redhat

Source activity

Repeated readings are counted rather than listed.

1× Official description updated · Oct 15, 2026 – Oct 15, 2026

References

2 on the record

access.redhat.com/security/cve/CVE-2026-6426
vdb-entry, x_refsource_REDHAT, NIST National Vulnerability Database
bugzilla.redhat.com/show_bug.cgi
issue-tracking, x_refsource_REDHAT, NIST National Vulnerability Database

Elsewhere on this site

Red Hat
every CVE for this vendor

CWE-681
other pages naming this weakness

Related CVEs (same products)

Medium CVE-2026-89096 Nfs-utils: nfs-utils: denial of service via memory leak in rpc.statd 15m
Medium CVE-2026-89088 Parted: parted: denial of service via heap buffer overflow during fat16 resize 15m
Medium CVE-2026-89085 Parted: parted: heap-based buffer overflow via crafted fat32 filesystem image 15m
Medium CVE-2026-111802 Nautilus: nautilus: arbitrary file deletion via trash symlink 15m
Low CVE-2026-17591 Libarchive: libarchive: use-after-free via aliased mac metadata copy 15m
Medium CVE-2026-62438 Gimp: gimp: paa integer overflow out-of-bounds read 1h

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No fixed version, patch or mitigation documented.
No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-6426 is "Qemu-kvm: vhost inflight migration vmstate integer type mismatch causes out-of-bounds access", rated Medium. It affects Red Hat Enterprise Linux 10 (Red Hat); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 4.4 describes technical severity. EPSS 0.39% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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