dbcve.org
Linux KernelOperating system · Linux

CVE-2006-6535

HIGH · 9.4 CVSS v2.0 Published 2007-01-30
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
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 dev_queue_xmit function in Linux kernel 2.6 can fail before calling the local_bh_disable function, which could lead to data corruption and "node lockups." NOTE: it is not clear whether this issue is exploitable.

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 dev_queue_xmit function in Linux kernel 2.6 has a race condition where it can fail before calling local_bh_disable, which protects against concurrent bottom-half interrupts. This ordering issue in the network transmission path could lead to data corruption and system-wide node lockups. The exploitability is uncertain.

MitigationUpgrade Linux kernel 2.6 to a patched version that corrects the dev_queue_xmit/local_bh_disable ordering, or apply the specific upstream kernel patch addressing this race condition.

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:= 2.6.0

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
Network
Complexity
Low
Authentication
None
Confidentiality
None
Integrity
Complete
Availability
Complete

AV:N/AC:L/Au:N/C:N/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 the running kernel version
    Run 'uname -r' or 'cat /proc/version' to determine the exact kernel version currently in use
    Affected if The version shown is exactly 2.6.0 (the only affected version listed)
  2. Compare version against affected range
    Verify if the installed kernel matches version 2.6.0 exactly - note that only this specific version is affected
    Affected if The kernel version is precisely 2.6.0 rather than any other 2.6.x release (such as 2.6.1, 2.6.2, etc.)
  3. Confirm network stack is active
    Verify the network interface subsystem is loaded and active by checking 'ifconfig -a' or 'ip link show'
    Affected if Network interfaces are present and the kernel network transmission path (dev_queue_xmit) is being used - this is the code path containing the race condition

A system is affected only if it is running exactly Linux kernel version 2.6.0 and using network transmission functionality, as later 2.6.x versions contain the corrected ordering of dev_queue_xmit relative to local_bh_disable.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade Linux kernel 2.6 to a patched version that corrects the dev_queue_xmit/local_bh_disable ordering, or apply the specific upstream kernel patch addressing this race condition.

Recommended fix Moderate confidence

Upgrade to a newer stable kernel release (2.6.x later point release or preferably a 3.x/4.x/5.x/6.x stable release for better security)

  1. 1. Identify the current kernel version using 'uname -r'
  2. 2. Check if your distribution has a newer kernel package available that addresses this vulnerability
  3. 3. For enterprise Linux distributions (RHEL, CentOS, etc.), apply the latest kernel security updates via your package manager (e.g., 'yum update kernel' or 'dnf update kernel')
  4. 4. For Debian/Ubuntu-based systems, run 'apt-get update && apt-get dist-upgrade' or 'apt-get install linux-image-generic' to get newer kernel packages
  5. 5. After updating the kernel package, reboot the system to load the fixed kernel
  6. 6. Verify the new kernel version is running using 'uname -r'
Caveat Kernel upgrades may require rebuild of proprietary kernel modules (drivers). Ensure compatibility of critical applications with the new kernel version 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
  • Consultation6.0 h
  • Implementation12.0 h
  • Testing10.0 h
  • Review / QA4.0 h
32.0 hours of engineering $5,580
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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-2006-6535 in production — separate from our analysis above.

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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
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