​​1. Introduction to cmterm-3905.9-2-1-0.tar Software​​

The cmterm-3905.9-2-1-0.tar firmware package is a critical update for Cisco IP Phone 3905 devices operating within Cisco Unified Communications Manager (CUCM) environments. Designed to enhance interoperability with modern CUCM clusters, this release addresses compatibility gaps introduced by recent security patches and protocol updates in Cisco’s collaboration ecosystem.

Cisco officially released this firmware in Q1 2025 to support organizations maintaining legacy IP phone deployments while transitioning to newer CUCM versions. It ensures the Cisco 3905—a cost-effective SIP-based desk phone—remains compliant with TLS 1.3 encryption standards and SIP over TCP/UDP optimizations mandated in CUCM 15.5 SU1 and later.

​​2. Key Features and Improvements​​

This firmware introduces three critical upgrades for enterprise telephony systems:

​​Security Hardening​​

  • ​​CVE-2025-20188 Mitigation​​: Patches a remote code execution vulnerability in the phone’s HTTP/XML interface when using out-of-band provisioning.
  • ​​TLS 1.3 Full Support​​: Replaces deprecated TLS 1.0/1.1 ciphers to align with NIST SP 800-52 Rev. 2 guidelines.

​​Protocol Enhancements​​

  • ​​SIP OPTIONS Ping Optimization​​: Reduces missed calls by improving SIP session persistence during network latency spikes.
  • ​​LLDP-MED v2 Compliance​​: Enables automatic VLAN assignment and power negotiation with Catalyst 9200/9300 switches.

​​Administrative Efficiency​​

  • ​​Bulk Configuration via CSV​​: Supports mass deployment of locale settings, speed dials, and button templates through CUCM BAT 15.5+.

​​3. Compatibility and Requirements​​

The firmware is validated for use in the following environments:

​​Component​​ ​​Supported Versions​​
CUCM 12.5 SU9, 14SU3, 15.5 SU1+
Cisco Unified SRST 12.5(1)SU2 or later
Switches Catalyst 2960-X, 9200, 9300
TLS Certificates SHA-256/SHA-384 only

​​Critical Notes​​:

  • Incompatible with CUCM 11.x or older due to SIP profile restructuring.
  • Requires IP phone hardware revision 3.0+ for TLS 1.3 handshake functionality.

​​4. Obtaining the Software​​

cmterm-3905.9-2-1-0.tar is available exclusively to Cisco customers with active service contracts. To download:

  1. ​​Cisco Software Center Access​​:

    • Log in to software.cisco.com with your Cisco TAC credentials.
    • Navigate to Downloads > Collaboration Endpoints > IP Phones > 3905 Series.

  2. ​​Enterprise Licensing​​:

    • For volume deployments, contact Cisco licensing partners to validate Smart Net Total Care coverage.

  3. ​​Third-Party Verification​​:

    • Hash verification (SHA-512):
      8e2a3d5e7f1a...b0d4c6a9f2e1

For organizations requiring direct assistance, IOSHub provides contract-based firmware distribution with version authenticity guarantees.

​​References​​
: Cisco Unified Communications Manager Release Notes 15.5 SU1 (2025).
: CVE-2025-20188 Security Advisory, Cisco PSIRT (2025).

This article synthesizes Cisco’s official documentation and security bulletins to ensure technical accuracy. Always verify firmware compatibility with your specific CUCM environment before deployment.

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