A critical vulnerability, CVE-2025-32433, has been disclosed in the Erlang/OTP SSH, enabling unauthenticated remote code execution. Discovered by researchers from Ruhr University Bochum, this flaw has received the maximum severity score of 10.0. It impacts all devices running the Erlang/OTP SSH daemon, with an urgent recommendation to upgrade to versions 25.3.2.10 or 26.2.4. This vulnerability allows attackers to exploit improper handling of pre-authentication protocol messages within the SSH daemon, potentially compromising systems.
The flaw stems from an issue in how the SSH protocol messages are processed before authentication. Attackers can send connection protocol messages and gain control over systems by executing commands with the same privileges as the SSH daemon. In many cases, this daemon runs with root privileges, offering attackers full control over the affected system. Horizon3’s Attack Team successfully demonstrated the exploit, highlighting the flaw’s severity and ease of exploitation.
Organizations are advised to immediately upgrade to the fixed versions before public proof-of-concept exploits emerge. As the flaw is being actively researched, it is expected that proof-of-concept (PoC) exploits will soon become publicly available. In the meantime, companies and administrators must take proactive steps to protect their systems from being targeted by malicious actors who may exploit this vulnerability. Public PoCs would drastically increase the risk of mass exploitation.
For critical systems, such as industrial or mission-essential devices that cannot be updated easily, additional steps must be taken. It is recommended to restrict SSH access to trusted IP addresses or disable the SSH daemon if it’s not required. These interim measures can help mitigate the risk of exploitation until the necessary patches are applied to vulnerable systems.
