CVE-2007-1820
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 · uneditedNortel Networks CallPilot and Meridian Mail voicemail systems, when a mailbox has auto logon enabled, allow remote attackers to retrieve or remove messages, or reconfigure the mailbox, by spoofing Calling Number Identification (CNID, aka Caller ID).
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 confidenceNortel Networks CallPilot and Meridian Mail voicemail systems with auto logon enabled rely solely on Calling Number Identification (CNID/Caller ID) for authentication. Attackers can spoof their caller ID to impersonate legitimate users, enabling unauthorized access to retrieve or delete messages and reconfigure mailbox settings without credentials.
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 versionsall 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
- Complete
- Integrity
- Complete
- Availability
- Complete
AV:N/AC:M/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 checksWork through these to decide whether this CVE applies to you.
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Identify Nortel voicemail systemLocate and identify any Nortel CallPilot or Meridian Mail voicemail servers in your environment through network scans, asset inventories, or documentation reviewAffected if The system is running Nortel CallPilot or Meridian Mail voicemail software
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Check auto logon configurationAccess the voicemail administration interface or configuration files and verify whether the auto logon feature is enabled. This is typically found in the system settings, security settings, or login configuration optionsAffected if Auto logon is enabled and allows authentication based solely on incoming caller ID information
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Verify CNID-only authentication methodReview the authentication settings to confirm that Calling Number Identification (CNID/Caller ID) is being used as the sole verification method for auto logon access without requiring additional credentials such as a PINAffected if CNID-based authentication is configured as the primary or only method for mailbox access without supplementary verification
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Confirm accessible mailbox functionsTest or review configuration to determine if users can retrieve messages, delete messages, change greetings, or modify mailbox settings through the auto logon feature without entering a PIN or passwordAffected if The auto logon feature permits access to message retrieval, deletion, or mailbox configuration without requiring a PIN or password entry
You are affected if you have a Nortel CallPilot or Meridian Mail voicemail system with auto logon enabled and CNID-based authentication allowing access without additional credential verification.
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.
dbcve · scopedDisable the auto logon feature on affected voicemail systems and implement multi-factor authentication (such as PIN verification) to require proper credentials regardless of caller ID.
These are legacy Nortel products (Nortel went bankrupt in 2009) with no direct upgrade path. Consider migrating to modern unified communications platforms such as Avaya Aura, Microsoft Teams Voice, or similar contemporary solutions.
- 1. Identify all CallPilot and Meridian Mail voicemail systems in the environment
- 2. Disable the 'auto logon' feature for all mailboxes to prevent Caller ID spoofing attacks
- 3. Require explicit password authentication for voicemail access instead of relying on CNID/Caller ID
- 4. Implement additional authentication controls such as PIN changes and account lockout policies
- 5. Monitor voicemail access logs for suspicious activity
- 6. Consider network-level controls to restrict unauthorized access to voicemail system ports
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA4.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2007-1820 — 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-2007-1820 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