may also be susceptible to other well-documented SSH weaknesses if not fully patched: SSH Terrapin Prefix Truncation Weakness - Cisco Community
: The Shodan CVE database provides detailed summaries of known vulnerabilities, including their CVSS scores and affected products, allowing for rapid correlation with discovered banners.
The string is not a single specific vulnerability, but rather a standard software banner string emitted by Cisco enterprise devices (running Cisco IOS or IOS XE) when an external system initiates a connection over Secure Shell (SSH) on Port 22.
1. Authentication Bypass via RSA Public Key Flaw (CVE-2015-0235 / Similar) ssh-2.0-cisco-1.25 vulnerability
Data source: Security Operations Center informative findings. Step-by-Step Remediation Playbook
If you cannot perform an immediate maintenance reboot to upgrade the firmware, deploy these temporary mitigations to secure your infrastructure:
Cisco IOS Software Reverse SSH Denial of Service Vulnerability may also be susceptible to other well-documented SSH
SSH-2.0-Cisco-2.22 (IOS 15.9) SSH-2.0-Cisco-2.36 (IOS-XE 16.x)
Historically, when security teams or automated compliance scanners flag an "SSH-2.0-Cisco-1.25 vulnerability," they are generally targeting severe software vulnerabilities tied to specific Cisco platform code. Most notably, this includes the high-severity (CVE-2025-32433), alongside classic architectural issues like authentication bypasses (CVE-2015-0235/related flaws) and state-machine Denials of Service (CVE-2020-3200). Technical Background: What is the Cisco-1.25 Banner?
: A Man-in-the-Middle (MitM) attacker can downgrade the connection's security by deleting specific protocol messages during the handshake without the client or server noticing. Cisco Bug ID : CSCwi61646 . 2. Unauthenticated Remote Code Execution (CVE-2025-32433) Authentication Bypass via RSA Public Key Flaw (CVE-2015-0235
In early 2025, a critical vulnerability was identified in certain Cisco products where the SSH server was built using the .
As of late 2024 and early 2025, security reports indicated that hundreds of thousands of devices worldwide were still reporting the SSH-2.0-Cisco-1.25 banner.