CVE-2008-1521
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 · uneditedZyXEL Prestige routers, including P-660 and P-661 models with firmware 3.40(AGD.2) through 3.40(AHQ.3), allow remote authenticated users to gain privileges by accessing administrative URIs, as demonstrated by rpSysAdmin.html.
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 confidenceZyXEL Prestige P-660 and P-661 routers running firmware versions 3.40(AGD.2) through 3.40(AHQ.3) contain an authentication bypass vulnerability where remote authenticated users can access certain administrative URIs (such as rpSysAdmin.html) to escalate privileges beyond their intended access level.
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= h-d1= h-d3= hw-d1= 3.40CVSS 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
- Single
- Confidentiality
- Partial
- Integrity
- Partial
- Availability
- Partial
AV:N/AC:L/Au:S/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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Identify router modelAccess the router web admin interface or check the device label to confirm the model is ZyXEL Prestige 660, Prestige 661, or a device running Zynos firmware.Affected if Model is Prestige 660 (h-d1 or h-d3), Prestige 661 (hw-d1), or Zynos
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Check firmware versionLog into the router web admin interface and navigate to the status or firmware information page to view the currently installed firmware version. Compare it to the affected range 3.40(AGD.2) through 3.40(AHQ.3).Affected if Firmware version is 3.40(AGD.2), 3.40(AGD.3), 3.40(AHG.1), 3.40(AHG.2), 3.40(AHG.3), 3.40(AHG.4), 3.40(AHG.5), 3.40(AHQ.1), 3.40(AHQ.2), or 3.40(AHQ.3)
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Verify web admin interface is accessibleAttempt to access the router web admin interface from a remote location or check router ACL settings to determine if the administrative web pages (typically on ports 80 or 443) are exposed to untrusted networks.Affected if The web administrative interface is accessible from outside trusted network segments or from the WAN interface
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Check for suspicious admin URI accessReview router logs or web server access logs for requests to administrative URIs such as rpSysAdmin.html, rpAdmin.html, or similar privileged management pages that may indicate privilege escalation attempts.Affected if Logs show access to administrative URIs like rpSysAdmin.html by users who should not have elevated privileges
A user is affected if they operate a ZyXEL Prestige 660/661 or Zynos router with firmware version 3.40(AGD.2) through 3.40(AHQ.3) and the router web administrative interface is accessible, allowing authenticated users to escalate privileges via vulnerable admin URIs.
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 dataUpgrade router firmware to a version beyond 3.40(AHQ.3). If upgrading is not possible, restrict access to the administrative web interface using ACLs or network segmentation to trusted IPs only.
- Consultation3.0 h
- Implementation4.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2008-1521 — 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-2008-1521 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
- No weaponised exploit code, or anything meant to cause harm
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