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Linux KernelOperating system · Linux

CVE-2015-8104

CRITICAL · 10.0 CVSS v3.1 Published 2015-11-16
Fix available
A fix is available. Upgrade to after 5.0.13 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click Patch available

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 KVM subsystem in the Linux kernel through 4.2.6, and Xen 4.3.x through 4.6.x, allows guest OS users to cause a denial of service (host OS panic or hang) by triggering many #DB (aka Debug) exceptions, related to svm.c.

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

A denial of service vulnerability in the KVM (Kernel-based Virtual Machine) subsystem for AMD processors (SVM) and Xen hypervisors allows malicious guest virtual machines to trigger excessive #DB (Debug) exceptions, causing the host OS to panic or hang. The flaw is in the svm.c handling of debug exceptions.

MitigationApply vendor patches to the Linux kernel (4.2.6 and later) or Xen hypervisor (4.3.x-4.6.x) that address the debug exception handling. Consider restricting untrusted VM access to sensitive workloads until patching is complete.

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
Linux KernelOperating system
Affected:<= 4.2.3
Debian LinuxOperating system
Affected:= 7.0= 8.0= 9.0
Ubuntu LinuxOperating system
Affected:= 12.04= 14.04= 15.04
XenOperating system
Affected:= 4.3.0= 4.3.1= 4.3.2= 4.3.3= 4.3.4= 4.4.0= 4.4.1= 4.4.2= 4.4.3= 4.5.0= 4.5.1= 4.5.2
SolarisOperating system
Affected:= 11.3
Vm VirtualboxApplication
Affected:>= 4.0.0, <= 4.0.34>= 4.1.0, <= 4.1.42>= 4.2.0, <= 4.2.34>= 4.3.0, <= 4.3.35>= 5.0.0, <= 5.0.13

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
Privileges
None
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/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 checks

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

  1. Check Linux kernel version
    Run 'uname -r' to get the running kernel version. Compare against the affected range: Linux <= 4.2.3
    Affected if Kernel version is 4.2.3 or lower
  2. Verify AMD SVM virtualization is in use
    On the host, check /proc/cpuinfo for 'svm' flag: grep -q 'svm' /proc/cpuinfo && echo 'SVM present'. Also check if KVM is loaded: lsmod | grep kvm_amd
    Affected if AMD SVM (svm) flag is present AND kernel is vulnerable AND KVM with AMD SVM is the hypervisor
  3. Check Xen hypervisor version
    Run 'xl info' or 'xm info' to get Xen version, or check /etc/xen/version if available. Compare against affected versions: 4.3.0-4.5.2
    Affected if Xen version is between 4.3.0 and 4.5.2 inclusive
  4. Check VirtualBox version
    Run 'VBoxManage --version' to get VirtualBox version. Compare against affected ranges: 4.0.0-4.0.34, 4.1.0-4.1.42, 4.2.0-4.2.34, 4.3.0-4.3.35, 5.0.0-5.0.13
    Affected if VirtualBox version falls within any of the affected ranges listed
  5. Confirm virtualization environment is AMD-based
    For KVM: verify the hypervisor is using AMD SVM (KVM with AMD processors). For Xen: verify the host CPU is AMD and SVM is enabled in the hypervisor. Check 'xl dmesg' or 'dmesg' for 'SVM' or 'AMD-V' indicators
    Affected if The virtualization environment uses AMD processors with SVM (AMD-V) virtualization and the hypervisor/kernel version is vulnerable

The environment is affected if running a vulnerable Linux kernel (4.2.3 or lower), Xen (4.3.x-4.5.x), or VirtualBox (4.0.x-5.0.x) version AND the system uses AMD processors with SVM (AMD-V) virtualization enabled.

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.

dbcve · scoped
Upgrade available Upgrade to a release after 5.0.13
Vendor patch git.kernel.org →
Interim mitigation

Apply vendor patches to the Linux kernel (4.2.6 and later) or Xen hypervisor (4.3.x-4.6.x) that address the debug exception handling. Consider restricting untrusted VM access to sensitive workloads until patching is complete.

Recommended fix High confidence

Linux Kernel 4.2.4 or later (or a distribution-specific kernel package that includes the CVE-2015-8104 fix)

  1. Identify the exact kernel version running on the system using 'uname -r'
  2. Check your distribution's security advisories for CVE-2015-8104 patches available for your specific version
  3. For Debian systems: run 'apt-get update && apt-get dist-upgrade' or install a newer kernel from backports
  4. For Ubuntu systems: run 'apt-get update && apt-get upgrade linux-image-generic' to get the patched kernel
  5. For Fedora/RHEL systems: run 'yum update kernel' or 'dnf update kernel'
  6. For SUSE systems: run 'zypper patch' or install kernel-default from the update repository
  7. After kernel installation, reboot the system to load the patched kernel
  8. Verify the running kernel version with 'uname -r' and confirm it is newer than 4.2.3
Caveat Kernel upgrades may require system reboot and could introduce compatibility issues with custom kernel modules or older drivers; test in staging environment before production deployment

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Linux Kernel Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing6.0 h
  • Review / QA3.0 h
15.0 hours of engineering $2,560
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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-2015-8104 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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