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QemuApplication

CVE-2015-5158

MEDIUM · 5.5 CVSS v3.1 Published 2016-04-12
Fix available
A fix is available. Upgrade to 2.4.0 or later.
See remediation →
57/100
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
Stack-based buffer overflow in hw/scsi/scsi-bus.c in QEMU, when built with SCSI-device emulation support, allows guest OS users with CAP_SYS_RAWIO permissions to cause a denial of service (instance crash) via an invalid opcode in a SCSI command descriptor block.

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

Stack-based buffer overflow in QEMU's SCSI device emulation (hw/scsi/scsi-bus.c) when built with SCSI support. Guest OS users with CAP_SYS_RAWIO permissions can trigger the overflow by sending an invalid opcode in a SCSI command descriptor block, causing the QEMU instance to crash.

MitigationUpdate QEMU to a patched version. Additionally, restrict CAP_SYS_RAWIO permissions for guest users and avoid exposing SCSI emulation to untrusted guests as a defense-in-depth measure.

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

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
QemuApplication
Affected:>= 2.2.0, < 2.4.0= 2.4.0

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
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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 'qemu-img --version' to find the installed QEMU version
    Affected if The version falls within 2.2.0 to 2.4.0 inclusive (>=2.2.0 and <2.4.0, or exactly 2.4.0)
  2. Confirm SCSI support is compiled in
    Check for the presence of scsi-bus.c or SCSI-related files in the QEMU build, or run 'qemu-system-x86_64 -device ?' and look for SCSI device options like 'lsi53c895a', 'virtio-scsi-pci', or 'scsi-hd'
    Affected if SCSI emulation support is present in the QEMU binary
  3. Determine if SCSI devices are exposed to guests
    Review the QEMU command line or VM configuration file for SCSI device definitions such as '-device scsi-hd', '-device scsi-cd', or '-device virtio-scsi-pci'
    Affected if A SCSI controller or disk is passed to the guest VM (this is the attack surface)
  4. Verify guest has CAP_SYS_RAWIO capability
    For QEMU instances using libvirt, run 'virsh dumpxml <vmname>' and check the <capabilities> section; for raw QEMU, check if the -enable-kvm flag is used with unprivileged guests
    Affected if The guest OS runs with elevated privileges or has CAP_SYS_RAWIO capability exposed to it

You are affected if your QEMU version is between 2.2.0 and 2.4.0 inclusive, the SCSI subsystem is compiled into your QEMU binary, and a SCSI device is currently passed to a guest VM with elevated privileges.

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
Upgrade available Upgrade to 2.4.0 or later
Fixed in 2.4.0
Interim mitigation

Update QEMU to a patched version. Additionally, restrict CAP_SYS_RAWIO permissions for guest users and avoid exposing SCSI emulation to untrusted guests as a defense-in-depth measure.

Fix this in Qemu Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing3.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,390
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An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,224.

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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-2015-5158 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
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data