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Unified Communications ManagerApplication · Cisco

CVE-2011-2561

HIGH · 7.1 CVSS v2.0 Published 2011-08-29
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
80/100
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 SIP process in Cisco Unified Communications Manager (aka CUCM, formerly CallManager) 7.x before 7.1(5b)su4 and 8.x before 8.0(1) does not properly handle SDP data within a SIP call in certain situations related to use of the g729ar8 codec for a Media Termination Point (MTP), which allows remote attackers to cause a denial of service (service outage) via a crafted call, aka Bug ID CSCtc61990.

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

A vulnerability exists in the SIP process of Cisco Unified Communications Manager (CUCM) versions 7.x before 7.1(5b)su4 and 8.x before 8.0(1) where the SIP process fails to properly validate SDP data containing the g729ar8 codec for Media Termination Points. A remote attacker can send a crafted SIP call with malicious SDP payload to trigger a service outage.

MitigationApply the vendor-supplied patches (CUCM 7.1(5b)su4 or later, or 8.0(1) or later) to resolve the SIP process vulnerability.

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
Unified Communications ManagerApplication
Affected:= 7.0\(1\)su1= 7.0\(1\)su1a= 7.0\(2\)= 7.0\(2a\)= 7.0\(2a\)su1= 7.0\(2a\)su2= 7.1\(2a\)= 7.1\(2a\)su1= 7.1\(2b\)= 7.1\(2b\)su1= 7.1\(3\)= 7.1\(3a\)

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
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 checks

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

  1. Identify the installed CUCM version
    Access the Cisco Unified Communications Manager Administration interface and navigate to 'System' > 'Version' to view the current version, or use the CLI command 'show version' via SSH to the CUCM server
    Affected if The installed version is 7.0(1)su1, 7.0(1)su1a, 7.0(2), 7.0(2a), 7.0(2a)su1, 7.0(2a)su2, 7.1(2a), 7.1(2a)su1, 7.1(2b), 7.1(2b)su1, 7.1(3), 7.1(3a), or any 7.x version prior to 7.1(5b)su4, or any 8.x version prior to 8.0(1)
  2. Confirm SIP service is enabled
    In CUCM Administration, navigate to 'Device' > 'Device Settings' > 'SIP Trunk Security Profile' or check if any SIP trunks or routes are configured under 'Device' > 'Trunk'
    Affected if SIP trunks or SIP-based communications are configured and active, making the SIP process reachable
  3. Verify Media Termination Points are configured
    In CUCM Administration, navigate to 'Device' > 'Media Resources' > 'Media Termination Point' to list any MTP devices configured in the system
    Affected if Any Media Termination Points are provisioned in the CUCM configuration
  4. Check for g729ar8 codec usage in SDP configurations
    Review SIP trunk configurations or MTP device settings for codec selection, particularly looking for g729ar8 or G729R8 entries in the supported codec lists
    Affected if The g729ar8 codec is enabled or permitted in any SIP-related codec configurations

The environment is affected if the CUCM version falls within the vulnerable 7.x or 8.x ranges AND SIP service with Media Termination Points is operational, regardless of whether g729ar8 codec is explicitly configured since the vulnerability is triggered by malformed SDP containing this codec.

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 the vendor-supplied patches (CUCM 7.1(5b)su4 or later, or 8.0(1) or later) to resolve the SIP process vulnerability.

Fix this in Unified Communications Manager Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA1.0 h
10.0 hours of engineering $1,750
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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-2011-2561 in production — separate from our analysis above.

No notes yet

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What this is

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.

What belongs here
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  • Version or environment caveats, and links to real fixes
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