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Ubuntu LinuxOperating system · Canonical

CVE-2008-4539

HIGH · 7.2 CVSS v2.0 Published 2008-12-29
Fix available
A fix is available. Upgrade to 0.10.0 or later.
See remediation →
77/100
Remediation priority · High
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
Heap-based buffer overflow in the Cirrus VGA implementation in (1) KVM before kvm-82 and (2) QEMU on Debian GNU/Linux and Ubuntu might allow local users to gain privileges by using the VNC console for a connection, aka the LGD-54XX "bitblt" heap overflow. NOTE: this issue exists because of an incorrect fix for CVE-2007-1320.

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

Heap-based buffer overflow in the Cirrus VGA graphics adapter emulation in QEMU and KVM. The vulnerability exists in the bitblt (bit block transfer) operation for the LGD-54XX display adapter. Local users can exploit this via the VNC console to gain elevated privileges. This issue is a regression from an incomplete fix for CVE-2007-1320.

MitigationUpgrade KVM to version kvm-82 or later, and apply vendor patches for affected Debian/Ubuntu systems. Restrict VNC access to trusted users and apply least-privilege principles to limit exposure.

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
Affected:= 8.04= 8.10
Debian LinuxOperating system
Affected:= 4.0= 5.0
KvmApplication
Affected:<= 81
QemuApplication
Affected:< 0.10.0

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
Local
Complexity
Low
Authentication
None
Confidentiality
Complete
Integrity
Complete
Availability
Complete

AV:L/AC:L/Au:N/C:C/I:C/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 QEMU or KVM installation and version
    Run 'qemu --version' or 'kvm --version' to determine the installed version. On Debian/Ubuntu, also check with 'dpkg -l | grep -E "qemu|kvm"'
    Affected if The installed version is QEMU < 0.10.0, or KVM <= 81, or the package version corresponds to Ubuntu 8.04/8.10 or Debian 4.0/5.0
  2. Confirm Cirrus VGA emulation is in use
    Examine the QEMU/KVM command line or configuration files for the '-vga cirrus' option, or check VM XML configuration for '<graphics type='vga' model='cirrus'>'
    Affected if The virtual machine is configured with Cirrus VGA ('-vga cirrus' or cirrus model) as the graphics adapter
  3. Verify VNC access is enabled
    Check the QEMU/KVM command line for '-vnc' option, or examine VM configuration for VNC graphics type. Look for listening VNC ports with 'netstat -tlnp | grep vnc' or 'ss -tlnp | grep vnc'
    Affected if VNC is enabled and accessible, exposing the graphics console over the network or to untrusted users
  4. Confirm the LGD-54XX bitblt operation is active
    This is implicit when Cirrus VGA runs with VNC; the vulnerability triggers during bit block transfer operations in the Cirrus emulated hardware. No specific command needed if steps 1-3 indicate exposure
    Affected if All three conditions are true: vulnerable QEMU/KVM version + Cirrus VGA + VNC access exposed to untrusted users

A system is affected if it runs QEMU < 0.10.0 or KVM <= 81 with Cirrus VGA emulation enabled and VNC access exposed, particularly on Ubuntu 8.04/8.10 or Debian 4.0/5.0 systems.

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 0.10.0 or later
Fixed in 0.10.0
Interim mitigation

Upgrade KVM to version kvm-82 or later, and apply vendor patches for affected Debian/Ubuntu systems. Restrict VNC access to trusted users and apply least-privilege principles to limit exposure.

Fix this in Ubuntu Linux Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,130
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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-2008-4539 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