Update to fixed Erlang/OTP versions or apply vendor-specific patches. Restrict SSH port access to authorized users via firewalls as a temporary mitigation. 3. Cisco IMC SSH Privilege Escalation (CVE-2025-20261)
| Product Family | Software Versions | Default SSH Config | Modulus Size | |----------------|-------------------|--------------------|---------------| | Cisco 2800, 3800 ISRs | IOS 12.4(24)T – 15.1(3)T | RSA modulus 1000 (125 bytes) | YES | | Catalyst 2960, 3560 switches | IOS 12.2(55)SE – 15.0(2)SE | RSA modulus 1024 (128 bytes) but downgradable to 1000 | Conditional | | ASA 5500 firewalls (8.x) | ASA 8.4 – 9.1 | SSHv2 with RSA 768 or 1024 | If manually set | | Nexus 3000, 5000 | NX-OS 5.x – 6.x | DSA or RSA 1024 | No (only if admin forces 1000) | ssh20cisco125 vulnerability
Most systems using these old SSH versions are now "zombie hardware" found in forgotten server rooms, making them prime targets for lateral movement. The Upgrade Cycle: This vulnerability forced the industry to move to Update to fixed Erlang/OTP versions or apply vendor-specific
: Specifies the target hardware running software ecosystems such as Cisco IOS, IOS XE, IOS XR, or NX-OS . These products often act as core infrastructure components,
According to Cisco's Security Advisory, multiple product lines are impacted. These products often act as core infrastructure components, making them high-value targets. The vulnerability is especially dangerous because it allows the attacker to gain control over the system, potentially resulting in full system compromise. Technical Breakdown of the Exploitation