Ubuntu LinuxOperating system · Canonical
CVE-2016-6351
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 · uneditedThe esp_do_dma function in hw/scsi/esp.c in QEMU (aka Quick Emulator), when built with ESP/NCR53C9x controller emulation support, allows local guest OS administrators to cause a denial of service (out-of-bounds write and QEMU process crash) or execute arbitrary code on the QEMU host via vectors involving DMA read into ESP command buffer.
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 confidenceVulnerability in QEMU's ESP/NCR53C9x controller emulation where the esp_do_dma function in hw/scsi/esp.c lacks proper bounds validation on DMA read operations into the ESP command buffer, allowing a malicious local guest administrator to write beyond buffer boundaries and potentially execute arbitrary code on the host or crash the QEMU process.
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
Ubuntu LinuxOperating system
= 12.04= 14.04= 16.04
Debian LinuxOperating system
= 8.0<= 2.6.2CVSS 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
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/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 checksWork through these to decide whether this CVE applies to you.
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Identify installed QEMU versionRun 'qemu-system-x86_64 --version' or 'qemu --version' to get the installed QEMU version numberAffected if The installed version is 2.6.2 or lower, or the version cannot be determined but the package is from an affected distribution (Ubuntu 12.04/14.04/16.04 or Debian 8.0)
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Check if ESP/NCR53C9x SCSI controller is emulatedReview QEMU command line arguments or libvirt domain XML configuration for '-device esp' or '<controller type='scsi' model='esp'>' specificationsAffected if The QEMU instance is configured to emulate the ESP (Fast SCSI) controller, which provides the attack surface for this vulnerability
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Identify running QEMU processes with ESP controllerRun 'ps aux | grep qemu' or check active libvirt domains with 'virsh list' and inspect domain configuration with 'virsh dumpxml <domain>' for ESP controller definitionsAffected if A QEMU virtual machine is actively running with the ESP SCSI controller emulated
A system is affected if it runs QEMU version 2.6.2 or lower with the ESP/NCR53C9x SCSI controller emulation enabled for any virtual machine
Generated from the published advisory. Verify against your own configuration.
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 dataUpdate QEMU to a patched version that properly validates DMA buffer bounds in the ESP controller emulation; alternatively, disable ESP/NCR53C9x controller emulation if not required for the guest workload.
Fix this in Ubuntu Linux
Scoped from the published advisory
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,088.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2016-6351 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2016-6351 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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