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Debian LinuxOperating system · Debian

CVE-2014-7815

MEDIUM · 5.0 CVSS v2.0 Published 2014-11-14
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
59/100
Remediation priority · Elevated
Remotely reachable No privileges 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
The set_pixel_format function in ui/vnc.c in QEMU allows remote attackers to cause a denial of service (crash) via a small bytes_per_pixel value.

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

The set_pixel_format function in QEMU's VNC server (ui/vnc.c) lacks proper validation of the bytes_per_pixel value supplied by remote clients. Attackers connecting via VNC can send a crafted pixel format request with an excessively small bytes_per_pixel value, triggering a crash (denial of service).

MitigationRestrict VNC access to trusted networks only and apply the relevant QEMU security patch, which adds bounds checking for the bytes_per_pixel value before it's used in memory operations.

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
Debian LinuxOperating system
Affected:= 7.0
Enterprise Linux DesktopOperating system
Affected:= 7.0
Enterprise Linux EusOperating system
Affected:= 7.3= 7.4= 7.5= 7.6= 7.7
Enterprise Linux ServerOperating system
Affected:= 7.0
Enterprise Linux Server AusOperating system
Affected:= 7.3= 7.4= 7.6= 7.7
Enterprise Linux WorkstationOperating system
Affected:= 7.0
VirtualizationApplication
Affected:= 3.0
Ubuntu LinuxOperating system
Affected:= 10.04= 12.04= 14.04= 14.10

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
Network
Complexity
Low
Authentication
None
Confidentiality
None
Integrity
None
Availability
Partial

AV:N/AC:L/Au:N/C:N/I:N/A:P

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 installation and version
    Run 'qemu-system-x86_64 --version' or check package manager output (dpkg -l qemu-system-x86 or rpm -qi qemu-kvm) to determine the installed QEMU version
    Affected if The installed version matches one of the affected versions listed in the CVE (Debian 7.0, RHEL 7.0-7.7, Ubuntu 10.04-14.10)
  2. Verify VNC server is enabled in QEMU
    Check QEMU command-line arguments or VM configuration for VNC options such as '-vnc :5900' or 'vnc' parameter in libvirt XML configuration
    Affected if VNC display is configured and enabled for the virtual machine
  3. Confirm network exposure of VNC port
    Check listening ports with 'netstat -tlnp | grep 5900' or 'ss -tlnp | grep vnc' and verify the bind address; examine firewall rules and network ACLs controlling access to port 5900
    Affected if The VNC port is bound to 0.0.0.0 or accessible from networks outside the trusted administrative segment

You are affected if you are running a vulnerable QEMU version with VNC enabled and the VNC service is accessible to untrusted network segments.

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

Restrict VNC access to trusted networks only and apply the relevant QEMU security patch, which adds bounds checking for the bytes_per_pixel value before it's used in memory operations.

Fix this in Debian Linux Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing3.0 h
  • Review / QA2.0 h
10.0 hours of engineering $1,750
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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-2014-7815 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