Ssh-2.0-cisco-1.25 Vulnerability [Free Access]

: Terrapin targets the handshake phase of the SSH protocol. It manipulates sequence numbers during the extension negotiation phase.

In 2025, Cisco announced CVE-2025-20159, a critical vulnerability affecting the management interface ACL processing in Cisco IOS XR Software. This vulnerability allows an unauthenticated, remote attacker to completely bypass configured access control lists (ACLs) for SSH, NetConf, and gRPC features. This is a severe failure because management ACLs are intended to be the last line of defense, restricting which IP addresses can reach the device's management plane. A bypass renders these access rules completely ineffective. ssh-2.0-cisco-1.25 vulnerability

: Under specific, highly structured traffic patterns, the software's internal SSH state machine fails to resolve out-of-sequence errors correctly. : Terrapin targets the handshake phase of the SSH protocol

0 Helpful. Georg Pauwen. VIP Alumni. ‎02-16-2021 12:30 AM. Hello, I think the '1.25' part is the Cisco specific vendor version ID. Cisco Community : Under specific, highly structured traffic patterns, the