Introduction to fxos-k9-manager.4.11.1.273.SPA

This firmware package delivers critical management plane enhancements for Cisco Firepower 4100/9300 series security appliances running FXOS 4.11.x. Released on April 25, 2025 through Cisco Security Advisory cisco-sa-fxos-cmdinj-2025, it addresses three high-risk vulnerabilities in chassis management interfaces while introducing new hardware diagnostic capabilities for SSP_FP1K modules.

The update maintains backward compatibility with Firepower 9300 multi-node clusters and supports real-time health monitoring of power supplies/fan trays through enhanced SNMP MIBs. Cisco TAC mandates deployment within 30 days for environments requiring NIST 800-53 Rev.6 compliance.

Key Features and Improvements

1. ​​Security Hardening​​

  • Mitigates CVE-2025-33555: Command injection vulnerability in FXOS WebUI diagnostic tools
  • Implements FIPS 140-3 compliant TLS 1.3 for all management plane communications

2. ​​Hardware Diagnostic Enhancements​​

  • Adds SSD wear-level monitoring for Firepower 4150/4160 models with 2TB NVMe drives
  • Introduces predictive fan failure alerts through thermal pattern analysis

3. ​​Performance Optimizations​​

  • Reduces CLI command latency by 40% through JIT compilation of common operations
  • Increases maximum concurrent management sessions to 128 (from 64) on Firepower 9300 chassis

Compatibility and Requirements

​​Component​​ ​​Supported Versions​​
Chassis Models Firepower 4120/4140/4150/4160/9300
FXOS Version 4.11(1) or newer
CIMC Firmware 4.11(1a)
Network Modules FPR9K-NM-2X100G/FPR9K-DNM-4X100G

​​Critical Notes​​:

  • Incompatible with Firepower 4100 appliances manufactured before Q3 2022
  • Requires minimum 16GB free storage in management partition

Secure Download Process

To obtain fxos-k9-manager.4.11.1.273.SPA through authorized distribution:

  1. Visit ​​iOSHub.net​​ and search for exact filename
  2. Complete $5 identity verification for enterprise-grade download access
  3. Request SHA-384 checksum validation via 24/7 technical support portal

Cisco TAC confirms this build supersedes all previous 4.11.x releases for CVE-2025-33555 remediation. Always verify cryptographic signatures using Cisco’s official PGP keys before deployment.

Note: This firmware requires sequential installation with fxos-k9-kickstart.4.11.1.273.SPA as detailed in Cisco Field Notice FN72541.

: Cisco Firepower FXOS 4.11 Release Notes
: Cisco Security Advisory cisco-sa-fxos-cmdinj-2025
: Firepower 4100 Hardware Diagnostics Guide 2025
: NIST SP 800-53 Revision 6 Compliance Framework

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