dbcve.org
Enterprise Linux DesktopOperating system · Redhat

CVE-2014-7840

HIGH · 7.5 CVSS v2.0 Published 2014-12-12
Fix available
A fix is available. Upgrade to after 2.1.3 or later.
See remediation →
84/100
Remediation priority · High
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 host_from_stream_offset function in arch_init.c in QEMU, when loading RAM during migration, allows remote attackers to execute arbitrary code via a crafted (1) offset or (2) length value in savevm data.

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 code execution vulnerability exists in QEMU's arch_init.c during RAM migration. The host_from_stream_offset function fails to properly validate offset and length values from incoming savevm data, allowing remote attackers to supply crafted values that can lead to arbitrary code execution.

MitigationUpgrade QEMU to a version with the bounds checking fix applied. If immediate upgrade is not possible, restrict migration traffic to trusted sources using TLS or VPN tunnels, and disable migration if not needed.

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
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
QemuApplication
Affected:<= 2.1.3

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
Partial
Integrity
Partial
Availability
Partial

AV:N/AC:L/Au:N/C:P/I:P/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. Check installed QEMU version
    Run 'rpm -qa | grep qemu' or 'qemu-system-x86_64 --version' to find the installed QEMU packages and their versions
    Affected if The installed version is QEMU <= 2.1.3 or matches any of the affected Red Hat versions listed (RHEL 7.0, 7.3-7.7, RHV 3.0)
  2. Verify QEMU migration listener is enabled
    Check for running QEMU instances with migration ports open: run 'ss -tlnp | grep -E "migrate|qemu"' or review libvirt domain XML for '<migration>' transport listen configuration
    Affected if QEMU is listening on migration ports (typically TCP ports 0-65535, commonly 49152-49161) or has migration mode enabled in the domain configuration
  3. Identify QEMU process command line
    Run 'ps aux | grep qemu' or 'virsh list --all' to find running QEMU virtual machines and their associated QEMU processes
    Affected if QEMU processes are running and the host participates in live migration as a destination (receives migration data)
  4. Confirm arch_init component is present
    Verify the QEMU binary includes the arch_init.c module by checking the binary path: 'ls -la /usr/bin/qemu-system-*' or check the package contents with 'rpm -ql <qemu-package>'
    Affected if The system has QEMU binaries present that include the migration code path (ram_load_host_from_stream in arch_init.c)

A system is affected if it runs QEMU version 2.1.3 or earlier, or a listed Red Hat variant (RHEL 7.0/7.3-7.7, RHV 3.0), and has migration listener enabled to receive incoming migration traffic from untrusted sources.

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 a release after 2.1.3
Interim mitigation

Upgrade QEMU to a version with the bounds checking fix applied. If immediate upgrade is not possible, restrict migration traffic to trusted sources using TLS or VPN tunnels, and disable migration if not needed.

Fix this in Enterprise Linux Desktop Scoped from the published advisory
  • Consultation4.0 h
  • Implementation2.0 h
  • Testing6.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,420
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An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,872.

Scan for this in your stack

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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-2014-7840 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