dbcve.org
LibvirtApplication · Redhat

CVE-2013-6456

MEDIUM · 5.8 CVSS v2.0 Published 2014-04-15
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
60/100
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
The LXC driver (lxc/lxc_driver.c) in libvirt 1.0.1 through 1.2.1 allows local users to (1) delete arbitrary host devices via the virDomainDeviceDettach API and a symlink attack on /dev in the container; (2) create arbitrary nodes (mknod) via the virDomainDeviceAttach API and a symlink attack on /dev in the container; and cause a denial of service (shutdown or reboot host OS) via the (3) virDomainShutdown or (4) virDomainReboot API and a symlink attack on /dev/initctl in the container, related to "paths under /proc/$PID/root" and the virInitctlSetRunLevel function.

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 · high confidence

LXC driver in libvirt 1.0.1-1.2.1 improperly validates symlinks in /dev within containers, allowing local users to manipulate host devices via virDomainDeviceAttach/Detach APIs through symlink attacks, and cause host DoS via virDomainShutdown/Reboot APIs by targeting /dev/initctl through symlinks that resolve outside the container namespace due to incomplete path sanitization under /proc/$PID/root.

MitigationUpgrade libvirt to version 1.2.2 or later which contains the fix; alternatively, implement proper symlink validation to prevent traversal outside container /dev directory and restrict device manipulation APIs for untrusted containers.

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
LibvirtApplication
Affected:= 1.0.1= 1.0.2= 1.0.3= 1.0.4= 1.0.5= 1.0.5.1= 1.0.5.2= 1.0.5.3= 1.0.5.4= 1.0.5.5= 1.0.5.6= 1.0.6
FedoraOperating system
Affected:= 20

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
Adjacent
Complexity
M
Authentication
Single
Confidentiality
None
Integrity
Partial
Availability
Complete

AV:A/AC:M/Au:S/C:N/I:P/A:C

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 installed libvirt version
    Run 'rpm -q libvirt' (RHEL/Fedora) or 'dpkg -l libvirt-daemon' (Debian/Ubuntu) to find the installed package version, or use 'virsh --version' to get the libvirt version number
    Affected if The version matches 1.0.1, 1.0.2, 1.0.3, 1.0.4, 1.0.5, 1.0.5.1, 1.0.5.2, 1.0.5.3, 1.0.5.4, 1.0.5.5, 1.0.5.6, or 1.0.6 (for Red Hat builds), or if running Fedora 20 with these libvirt versions
  2. Confirm LXC driver is in use
    Check running libvirt domains with 'virsh list --all' and inspect domain XML configs with 'virsh dumpxml <domain>' to identify domains using LXC (look for '<os><type>hvm</type></os>' with '<loader>' for QEMU, or check for LXC-specific configuration elements)
    Affected if Any LXC container domains are defined and running on the affected libvirt version
  3. Check for symlinks in container /dev directories
    Examine /dev within running container namespaces - list contents of /dev for container processes using 'ls -la /proc/<container_pid>/root/dev/' and look for symlinks pointing outside the container (symlinks with '->' pointing to paths like /dev/initctl or /dev/tty)
    Affected if Symlinks exist in container /dev directories that point to host device paths or resolve outside the container namespace, particularly entries targeting /dev/initctl or other host devices
  4. Verify device attachment capability is exposed
    Review container XML configuration for passthrough device assignments or check if untrusted users have access to virDomainDeviceAttach/Detach APIs via libvirt ACLs or policy files
    Affected if Container configurations allow device passthrough or untrusted users have permissions to attach/detach devices to containers

A system is affected if it runs libvirt versions 1.0.1 through 1.0.6 with active LXC containers, particularly if those containers expose device manipulation APIs to untrusted users or contain symlinks in /dev that could traverse outside the container namespace.

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

Upgrade libvirt to version 1.2.2 or later which contains the fix; alternatively, implement proper symlink validation to prevent traversal outside container /dev directory and restrict device manipulation APIs for untrusted containers.

Fix this in Libvirt Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,930
Get help mitigating

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 locally
dbcve dependency scanner

Check whether your project pulls in CVE-2013-6456 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

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-2013-6456 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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