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Meridian Option 11cApplication · Nortel

CVE-2007-5591

HIGH · 7.8 CVSS v2.0 Published 2007-10-19
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
87/100
Remediation priority · High
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 CS1000 signaling server in Nortel Enterprise VoIP-Core-CS 1000M Chassis/Cabinet, Enterprise VoIP-Core-CS 1000E and 1000S, Meridian-Core-Option 11C Chassis and Cabinet, and Meridian-Core-Option 51C, 61C, and 81C allows remote attackers to cause a denial of service (telephony application outage) via a flood of packets to Embedded LAN (ELAN) ports.

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 confidence

This is a network-based denial of service vulnerability in Nortel CS 1000 and Meridian VoIP signaling servers. Remote attackers can flood packets to the Embedded LAN (ELAN) ports, causing the telephony application to become unavailable. The attack requires only network access to the ELAN interfaces, making it exploitable by any adjacent or external attacker capable of sending traffic to the affected ports.

MitigationApply network-based rate limiting or filtering on ELAN port interfaces to mitigate packet flooding. Consider network segmentation to restrict access to ELAN ports, and investigate vendor-supplied patches for these legacy Nortel systems.

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
Meridian Option 11cApplication
Affected:all versions
Meridian Option 51cApplication
Affected:all versions
Meridian Option 61cApplication
Affected:all versions
Meridian Option 81cApplication
Affected:all versions
Voip Core CsApplication
Affected:= 1000e= 1000m= 1000s

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
None
Availability
Complete

AV:N/AC:L/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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify Nortel Meridian PBX systems in inventory
    Search asset inventory or physically inspect equipment for Nortel Meridian Option 11c, 51c, 61c, or 81c PBX systems. Check system documentation or run network discovery scans for Nortel device signatures.
    Affected if Any of these four Meridian Option models are present in the environment.
  2. Identify Nortel CS 1000 VoIP systems in inventory
    Search asset inventory for Nortel CS 1000 systems, specifically models 1000e, 1000m, or 1000s. Check VoIP infrastructure documentation or use network discovery to identify these devices.
    Affected if Any CS 1000 model (1000e, 1000m, or 1000s) is deployed.
  3. Verify ELAN port network accessibility
    Identify the Embedded LAN (ELAN) interface IP addresses on the Nortel systems. Use network scanning (nmap or similar) to probe for ELAN port accessibility. Common ELAN ports are typically UDP-based VoIP signaling ports; consult system documentation for specific port numbers if available.
    Affected if ELAN ports are reachable from network segments accessible to untrusted users or external attackers.
  4. Check if ELAN interfaces lack rate limiting or traffic filtering
    Review network device configurations (switches, firewalls, routers) between untrusted networks and the ELAN interfaces. Verify whether any rate limiting, access control lists, or traffic shaping is applied to packets destined for ELAN ports.
    Affected if No rate limiting or ACL filtering is configured on the network path to ELAN interfaces.

A user is affected if they have any Nortel Meridian Option 11c/51c/61c/81c or CS 1000 (1000e/1000m/1000s) system with accessible ELAN ports and no network-level protection against packet flooding.

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.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply network-based rate limiting or filtering on ELAN port interfaces to mitigate packet flooding. Consider network segmentation to restrict access to ELAN ports, and investigate vendor-supplied patches for these legacy Nortel systems.

Fix this in Meridian Option 11c Scoped from the published advisory
  • Consultation6.0 h
  • Implementation12.0 h
  • Testing6.0 h
  • Review / QA4.0 h
28.0 hours of engineering $4,980
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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-2007-5591 in production — separate from our analysis above.

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