CVE-2006-6263
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 · uneditedTeredo clients, when source routing is enabled, recognize a Routing header in an encapsulated IPv6 packet and send the packet to the next hop, which might allow remote attackers to bypass policies of certain Internet gateways that drop all source-routed packets.
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 confidenceThis vulnerability affects Teredo clients when source routing is enabled. The Teredo client will recognize and process a Routing header within an encapsulated IPv6 packet, forwarding it to the next hop rather than treating it as a dropped source-routed packet, allowing attackers to bypass Internet gateway policies that block source-routed traffic.
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 dataall versionsCVSS 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
- M
- Authentication
- None
- Confidentiality
- Partial
- Integrity
- Partial
- Availability
- Partial
AV:N/AC:M/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 checksWork through these to decide whether this CVE applies to you.
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Check if Teredo client is enabledRun 'netsh interface teredo show state' to see Teredo status. Also check 'netsh interface ipv6 show teredo' on older Windows versions.Affected if Teredo shows as 'Enabled' or 'Client' rather than 'Disabled' or 'Offline'
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Verify source routing is permitted on the systemRun 'netsh interface ipv6 show route' to view routing table. Check registry key HKLM\System\CurrentControlSet\Services\Tcpip6\Parameters\DisableIPSourceRouting (if it exists and is set to 0 or 1, source routing is enabled).Affected if DisableIPSourceRouting is set to 0 (enabled) or 1 (enabled with loopback), or no restriction is configured
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Confirm Teredo interface is activeRun 'ipconfig /all' and look for 'Teredo Tunneling Pseudo-Interface' with an IPv6 address assigned, or run 'netsh interface teredo show state' to verify the interface is online.Affected if Teredo tunneling interface exists and shows an active IPv6 address (typically 2001::/32 prefix)
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Check if firewall permits IPv6 routing header packetsReview Windows Firewall rules for IPv6 inbound rules, specifically any rules allowing traffic with Routing header type (extension header type 43). Use 'netsh advfirewall firewall show rule name=all' to inspect.Affected if Inbound IPv6 rules explicitly allow packets with Routing headers, or no rules explicitly block them
System is affected if Teredo client is enabled and source routing is not disabled at the OS or network level, allowing processing of IPv6 Routing headers within Teredo-encapsulated traffic.
Generated from the published advisory. Verify against your own configuration.
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 dataDisable source routing functionality on Teredo clients, or configure network firewalls and edge devices to explicitly drop all packets containing IPv6 Routing headers regardless of encapsulation.
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,800.
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Free · runs locallyCheck whether your project pulls in CVE-2006-6263 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2006-6263 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
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