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Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 11 Feb 2026.
Unified Communications ManagerApplication · Cisco

CVE-2026-20045

CRITICAL · 9.8 CVSS v3.1 Published 2026-01-21
Fix available
A fix is available. Upgrade to 14su5 or later.
See remediation →
100/100
Remediation priority · Urgent
In the wild 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 Cisco Unified Communications Manager (Unified CM), Cisco Unified Communications Manager Session Management Edition (Unified CM SME), Cisco Unified Communications Manager IM & Presence Service (Unified CM IM&P), Cisco Unity Connection, and Cisco Webex Calling Dedicated Instance could allow an unauthenticated, remote attacker to execute arbitrary commands on the underlying operating system of an affected device.  This vulnerability is due to improper validation of user-supplied input in HTTP requests. An attacker could exploit this vulnerability by sending a sequence of crafted HTTP requests to the web-based management interface of an affected device. A successful exploit could allow the attacker to obtain user-level access to the underlying operating system and then elevate privileges to root.  Note: Cisco has assigned this security advisory a Security Impact Rating (SIR) of Critical rather than High as the score indicates. The reason is that exploitation of this vulnerability could result in an attacker elevating privileges to root.

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

Command injection vulnerability in Cisco unified communications products (Unified CM, Unified CM SME, Unified CM IM&P, Unity Connection, Webex Calling DI). An unauthenticated remote attacker sends crafted HTTP requests to the web-based management interface, which fails to properly validate user input. Successful exploitation allows arbitrary OS command execution with user privileges, followed by privilege escalation to root.

MitigationApply Cisco security patches/updates for this vulnerability immediately. As an interim measure, restrict network access to the web-based management interface to trusted IP addresses only or disable it if unnecessary.

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, < 14su5>= 15.0, <= 15su3a
Unified Communications Manager Im And Presence ServiceApplication
Affected:>= 12.5, < 14su5>= 15.0, <= 15su3a
Unity ConnectionApplication
Affected:>= 12.5, < 14su5>= 15.0, <= 15su3

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
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/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 the installed product and version
    Access the Cisco Unified Communications Manager administrative interface and navigate to About > Version, or run 'show version' via CLI if you have console access. For Unity Connection, use the CLI command 'show version' or check via the administration page.
    Affected if The installed version falls within: CUCM/CUCM IM&P 12.5 to before 14su5, or 15.0 to 15su3a; Unity Connection 12.5 to before 14su5, or 15.0 to 15su3.
  2. Confirm web-based management interface is enabled
    In the Cisco Unified CM Administration page, go to System > Enterprise Parameters and verify the 'Web Interface' or 'Cisco Unified Communications Manager TFTP' services are enabled. For Unity Connection, check Service Management in the administration console.
    Affected if The web-based management interface is enabled and accessible.
  3. Verify network exposure of management interface
    Check firewall rules or access control lists that govern access to ports 443 and 8443 (HTTPS) and 80 and 8080 (HTTP) on the management interface IP. Determine if these ports are reachable from untrusted networks.
    Affected if The management interface HTTP/HTTPS ports are accessible from untrusted or external networks without proper network segmentation.
  4. Review recent HTTP access logs for suspicious patterns
    Examine web server logs in /var/log/httpd/ or the relevant log directory for the management interface. Look for unusual patterns such as shell metacharacters (;, |, &, $, `, etc.) in request URIs or parameters, especially from unauthenticated sources.
    Affected if Unusual HTTP requests containing command injection patterns are found in the logs, particularly from unauthenticated sources.

Your environment is likely affected if the installed product version is within the vulnerable ranges AND the web-based management interface is enabled and accessible to the network where the attacker resides.

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 14su5 or later
Fixed in 14su5
Interim mitigation

Apply Cisco security patches/updates for this vulnerability immediately. As an interim measure, restrict network access to the web-based management interface to trusted IP addresses only or disable it if unnecessary.

Recommended fix Moderate confidence

14SU5 or later / 15SU3b or later (Unified CM and IM&P); 14SU5 or later / 15SU4 or later (Unity Connection)

  1. 1. Identify the exact installed version of Cisco Unified Communications Manager, Unified CM IM & Presence Service, or Unity Connection using the web interface or CLI
  2. 2. For Unified Communications Manager and Unified CM IM&P: Upgrade to version 14SU5 or later, or 15SU3b or later
  3. 3. For Unity Connection: Upgrade to version 14SU5 or later, or 15SU4 or later
  4. 4. Download the appropriate update from the Cisco Software Download page (software.cisco.com) using valid credentials
  5. 5. Follow the standard Cisco upgrade procedure for the specific product, including backing up the current configuration
  6. 6. After upgrade, verify the system is operational and the vulnerability is resolved by checking the Cisco advisory
Caveat Ensure compatibility with existing integrations and review Cisco upgrade documentation for any specific prerequisites or migration steps

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

Fix this in Unified Communications Manager Exploited in the wild — priority engagement
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
Get it fixed fast

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,176.

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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-2026-20045 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
  • 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