CVE-2009-4293
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 · uneditedInternet Initiative Japan SEIL/X1, SEIL/X2, and SEIL/B1 firmware 2.30 through 2.51, when NAT is enabled, allows remote attackers to cause a denial of service (system restart) via crafted GRE 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 confidenceSEIL/X1, SEIL/X2, and SEIL/B1 router firmware versions 2.30-2.51 contain a vulnerability when NAT is enabled. Crafted GRE packets sent by remote attackers trigger a system restart, causing denial of service.
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= 2.30= 2.40= 2.41= 2.42= 2.50= 2.51all versions= 2.30= 2.40= 2.41= 2.42= 2.50= 2.51all versions= 2.30= 2.40= 2.41= 2.42= 2.50= 2.51all 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
- None
- Integrity
- None
- Availability
- Complete
AV:N/AC:M/Au:N/C:N/I:N/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 checksWork through these to decide whether this CVE applies to you.
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Identify router modelLog into the router administrative interface or check the device label to confirm the model is SEIL/X1, SEIL/X2, or SEIL/B1Affected if Model is any SEIL/X1, SEIL/X2, or SEIL/B1 variant
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Check firmware versionAccess the router firmware/version information page in the administrative web interface or run the equivalent CLI command (such as 'show version' or 'fwshow')Affected if Firmware version is 2.30, 2.40, 2.41, 2.42, 2.50, or 2.51
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Verify NAT is enabledNavigate to the NAT configuration section in the router web interface or run the CLI command to display NAT settings (such as 'show nat' or 'ip nat show')Affected if NAT function is enabled on any interface
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Confirm GRE is accessibleCheck if GRE protocol is configured or if the router is directly exposed to GRE traffic from untrusted networksAffected if GRE packets can reach the router from external sources
If the router is a SEIL/X1, SEIL/X2, or SEIL/B1 model running firmware versions 2.30-2.51 with NAT enabled and accessible to GRE traffic, the environment is affected by this vulnerability.
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 dataUpdate firmware beyond version 2.51. If immediate update is not feasible, consider blocking GRE traffic at upstream perimeter filters or disabling NAT if operationally acceptable until patch can be applied.
- Consultation4.0 h
- Implementation3.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,680.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2009-4293 — 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-2009-4293 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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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.
- 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