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Unified Communications ManagerApplication · Cisco

CVE-2024-20253

CRITICAL · 10.0 CVSS v3.1 Published 2024-01-26
Fix available
A fix is available. Upgrade to 12.5 / 14su3 or later.
See remediation →
100/100
Remediation priority · Urgent
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
A vulnerability in multiple Cisco Unified Communications and Contact Center Solutions products could allow an unauthenticated, remote attacker to execute arbitrary code on an affected device. This vulnerability is due to the improper processing of user-provided data that is being read into memory. An attacker could exploit this vulnerability by sending a crafted message to a listening port of an affected device. A successful exploit could allow the attacker to execute arbitrary commands on the underlying operating system with the privileges of the web services user. With access to the underlying operating system, the attacker could also establish root access on the affected device.

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 code injection vulnerability in Cisco Unified Communications and Contact Center Solutions allows unauthenticated remote attackers to send crafted messages to a listening port, causing improperly processed user data to be executed in memory. This enables arbitrary command execution with web services user privileges, which can then be escalated to root access on the underlying operating system.

MitigationApply Cisco-provided patches or updated software versions for affected Unified Communications and Contact Center products; restrict network access to listening ports and monitor for anomalous traffic patterns until patches are deployed.

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:< 12.5\(1\)su8>= 14.0, < 14su3
Unified Communications Manager Im And Presence ServiceApplication
Affected:< 12.5\(1\)su8>= 14.0, < 14.0su3
Unity ConnectionApplication
Affected:< 12.5\(1\)su8>= 14.0, < 14su3
Unified Contact Center ExpressApplication
Affected:= 12.5\(1\)
Virtualized Voice BrowserApplication
Affected:= 12.5\(1\)= 12.6\(1\)= 12.6\(2\)

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
Privileges
None
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

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 installed Cisco UC product
    Run 'show version' on the Cisco device or check installed packages. For virtual appliances, access the admin interface and navigate to About or System Information to confirm the product name (CUCM, IM/P, Unity Connection, UCCX, or VVB).
    Affected if The product is one of: Cisco Unified Communications Manager, Cisco Unified Communications Manager IM and Presence Service, Cisco Unity Connection, Cisco Unified Contact Center Express, or Cisco Virtualized Voice Browser.
  2. Determine the installed software version
    Execute 'show version' at the CLI prompt or check the version via the administration web interface under System > Version. Record the full version string including any_SU (service update) notation.
    Affected if The version falls into any of these ranges: CUCM < 12.5(1)su8, CUCM >= 14.0 and < 14su3, IM/P < 12.5(1)su8, IM/P >= 14.0 and < 14.0su3, Unity Connection < 12.5(1)su8, Unity Connection >= 14.0 and < 14su3, UCCX = 12.5(1), VVB = 12.5(1) or 12.6(1) or 12.6(2).
  3. Verify the vulnerability is exploitable
    Confirm that network services are listening on exposed ports. Use 'show control listen' or 'netstat -an | grep LISTEN' to identify listening ports. The vulnerability requires the web services port to be accessible to remote attackers.
    Affected if The affected product is running a vulnerable version AND the service port is accessible from untrusted networks (not behind a firewall or VPN).

You are affected if you are running any of the listed Cisco Unified Communications products at a version that matches the vulnerable ranges and the service port is network-accessible to untrusted users.

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.

dbcve · scoped
Upgrade available Upgrade to 12.5 / 14su3 / 14.0su3 or later
Fixed in 12.514su314.0su3
Interim mitigation

Apply Cisco-provided patches or updated software versions for affected Unified Communications and Contact Center products; restrict network access to listening ports and monitor for anomalous traffic patterns until patches are deployed.

Recommended fix High confidence

CUCM: 12.5(1)su8 or 14SU3; CUCM IM&P: 12.5(1)su8 or 14.0SU3; Unity Connection: 12.5(1)su8 or 14SU3; Others: Contact Cisco TAC

  1. 1. Identify the exact product and version running using the Cisco Unified Reporting tool or CLI command 'show version'
  2. 2. For Unified Communications Manager (CUCM): If running 12.5.x, upgrade to 12.5(1)su8 or later. If running 14.x, upgrade to 14SU3 or later
  3. 3. For Unified Communications Manager IM and Presence Service: If running 12.5.x, upgrade to 12.5(1)su8 or later. If running 14.0.x, upgrade to 14.0SU3 or later
  4. 4. For Unity Connection: If running 12.5.x, upgrade to 12.5(1)su8 or later. If running 14.x, upgrade to 14SU3 or later
  5. 5. For Unified Contact Center Express 12.5(1): Contact Cisco TAC for patch availability or upgrade path
  6. 6. For Virtualized Voice Browser 12.5(1), 12.6(1), or 12.6(2): Contact Cisco TAC for patch availability or upgrade path
  7. 7. After upgrade, verify the version using 'show version' and confirm the vulnerability is resolved
  8. 8. Review Cisco security advisory for any post-upgrade configuration requirements
Caveat Major upgrades between version families (e.g., 12.x to 14.x) may require significant testing and could have feature/behavior changes; coordinate maintenance window

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Unified Communications Manager Scoped from the published advisory
  • Consultation8.0 h
  • Implementation6.0 h
  • Testing8.0 h
  • Review / QA4.0 h
26.0 hours of engineering $4,600
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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-2024-20253 in production — separate from our analysis above.

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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
  • 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