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Heap-based Buffer OverflowWeakness · CWE-122

CVE-2026-48914

MEDIUM · 6.7 CVSS v3.1 Published 2026-06-12
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
69/100
Remediation priority · Elevated
Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
A flaw was found in QEMU's virtio-blk device. The issue arises because the device does not properly validate the size of input descriptors before writing data. A malicious guest with high privileges could exploit this vulnerability by submitting a malformed virtio-blk SCSI request, leading to an out-of-bounds write in the host heap memory and a potential denial of service (DoS) for the QEMU process.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

A flaw in QEMU's virtio-blk device allows a high-privilege malicious guest to submit malformed virtio-blk SCSI requests without proper input descriptor size validation, leading to an out-of-bounds write in host heap memory and potential denial of service.

MitigationApply the vendor patch to QEMU that adds proper input descriptor size validation before data writes in the virtio-blk device emulation code.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
High
User interaction
None
Scope
Changed
Confidentiality
None
Integrity
Low
Availability
High

CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:N/I:L/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify QEMU version
    Run 'qemu-system-x86_64 --version' or check installed package version (e.g., 'dpkg -l qemu-system-x86' or 'rpm -q qemu-kvm')
    Affected if The installed QEMU version matches the vulnerable release prior to the patch adding descriptor size validation
  2. Verify virtio-blk device is in use
    Inspect QEMU command line or libvirt domain XML for '-device virtio-blk-pci' or similar virtio-blk device configuration
    Affected if virtio-blk device emulation is enabled and attached to a guest VM
  3. Check for active QEMU processes with virtio-blk
    Run 'ps aux | grep qemu' and review process arguments for virtio-blk device parameters, or query libvirt with 'virsh dumpxml <domain>'
    Affected if A QEMU process is running with virtio-blk device backend for any guest
  4. Confirm guest high-privilege access is possible
    Review guest VM access controls and privilege levels - the flaw requires a high-privilege malicious user within the guest
    Affected if Untrusted or potentially malicious users have high-privilege (root/privileged) access to any guest using virtio-blk

The environment is affected if QEMU with a vulnerable version is running and exposes a virtio-blk device to any guest, especially guests with untrusted high-privilege users.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply the vendor patch to QEMU that adds proper input descriptor size validation before data writes in the virtio-blk device emulation code.

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing8.0 h
  • Review / QA4.0 h
24.0 hours of engineering $4,160
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-48914 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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