Ssh20cisco125 Vulnerability ((top)) Jun 2026

+---------------------------------------------+ | Application Layer (SSH-USERAUTH) | +---------------------------------------------+ | Authentication Layer (SSH-TRANS) | +---------------------------------------------+ | Transport & Key Exchange (Diffie-Hellman) | +---------------------------------------------+ | Cisco Platform POSIX/IOS Kernel | +---------------------------------------------+ The Three Structural Pillars of SSHv2:

: Maliciously crafted SSH connections can exhaust the device’s maximum concurrent process memory. This blocks legitimate administrators from accessing the device, effectively isolating the infrastructure layer. Technical Breakdown: The Threat Model ssh20cisco125 vulnerability

: A critical flaw in the Erlang/OTP SSH server used in some Cisco products allows unauthenticated Remote Code Execution (RCE) . Cisco has confirmed impact on products including ConfD

Cisco has confirmed impact on products including ConfD , Network Services Orchestrator (NSO) , and Ultra Cloud Core . This code can be used to: While the

Cisco provided several options to address these vulnerabilities:

The vulnerability can be exploited by an unauthenticated attacker who has access to the device via SSH-2. The attacker can send a malicious SSH-2 packet to the device, which will then execute the attacker's code. This code can be used to:

While the initial entry point for this attack chain was often the Web UI (HTTP/HTTPS), the end goal for attackers was to implant a backdoor that persisted on the device. Once the device was compromised, the malware (often implants like "BadEx()" or variations used by the Volt Typhoon group) allowed attackers to maintain persistence.