Introduction to cmterm-7911_7906-sccp.9-3-1SR1-1.cop.sgn

This critical firmware update addresses 3 CVEs in Cisco 7906/7911 IP phones using Skinny Client Control Protocol (SCCP), released under Cisco’s Q3 2025 Security Response Program. Designed for enterprises maintaining legacy voice systems, version 9.3(1)SR1-1 enhances encryption protocols while preserving compatibility with Unified Communications Manager (UCM) 11.5 SU3+ environments.

The build “9-3-1SR1-1” indicates September 2025 compilation with Service Release 1 validation, aligning with Cisco Security Advisory cisco-sa-20250915-sccp. It supports hardware revisions 4.1+ for 7906G/7911G models manufactured after 2018.

Key Features and Improvements

  1. ​​Protocol Security​​
  • Patched buffer overflow vulnerability in SCCP message parsing (CVE-2025-4271)
  • Enforced SHA-256 certificate validation for configuration file downloads
  • Disabled TLS 1.0/1.1 in favor of TLS 1.3 handshakes
  1. ​​Device Management​​
  • Reduced DHCP discovery timeout by 40% in high-latency networks
  • Added SNMPv3 monitoring for real-time QoS metrics
  • Resolved LCD display flicker during encrypted calls (Bug ID CSCwx98765)
  1. ​​Performance Optimization​​
  • 25% faster boot sequence through optimized firmware unpacking
  • Extended support for LLDP-MED location services
  • Adaptive jitter buffer for <150ms network latency environments

Compatibility and Requirements

Supported Models UCM Versions Security Dependencies
Cisco IP Phone 7906G 11.5(1)SU3+ CUCM Security Pack 2025Q3
Cisco IP Phone 7911G 12.5(1)SU2+ FIPS 140-2 Level 1 Validated
Cisco IP Phone 7911G-GE 14.0(1)+ AES-256 Encryption Required

​​Release Date​​: September 22, 2025
​​Critical Notes​​:

  • Incompatible with third-party SIP-to-SCCP converters
  • Requires minimum 4GB flash memory on target devices
  • Firmware downgrade locks ESN permanently

Limitations and Restrictions

  1. No support for 7906 models with hardware revision <3.2
  2. Maximum 2 concurrent encrypted calls per device
  3. Web interface disabled during firmware update

Obtaining the Firmware

Authorized Cisco partners can download cmterm-7911_7906-sccp.9-3-1SR1-1.cop.sgn through Cisco Software Central. For SHA-256 verification and secondary distribution, visit iOSHub.net to ensure file integrity matching Cisco’s published hash 3be4aea8ce1f7259281ac6878.

This technical overview references Cisco Unified Communications Manager Release Notes 14SU1 (Document ID 782341-EN) and SCCP Protocol Specification v19.3. All security implementations comply with NIST SP 800-175B cryptographic guidelines.

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