The vulnerability (CVE-2026-68956) in Erlang/OTP ssh allows an authenticated remote attacker to exhaust node memory by repeatedly opening session channels that are never assigned a handler. The 'session' clause of ssh_connection:handle_msg/4 only checks minimal_remote_max_packet_size before calling setup_session/5, which unconditionally creates a channel record stored in the ETS channel cache. The max_channels daemon option only limits supervisor children and does not account for channels without handlers, making the limit ineffective against this attack. According to RFC 4254 section 5.1, many session channels per connection are permitted, and each channel record consumes a few hundred bytes. Consequently, a single authenticated connection can accumulate many channels, exhausting memory and causing the Erlang emulator to terminate, impacting all applications running on the node. No sensitive data or write access is compromised. The affected OTP versions are from 18.1.2 up to but not including 27.3.4.18, 28.5.0.7, and 29.1.1, with corresponding ssh versions from 4.1.1 up to but not including 5.2.11.13, 5.5.2.6, and 6.0.6. Whether versions before 18.1.2 are affected is unknown. No vendor advisory or patch information is provided in the input.

An authenticated remote attacker can cause denial of service by exhausting the node's memory through repeated opening of unhandled session channels. This results in termination of the Erlang emulator, affecting all applications running on the node. There is no exposure of file contents, credentials, or write access.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Since the vulnerability requires authentication and exploits a resource exhaustion condition, monitor for unusual SSH session channel activity and consider limiting authenticated user access until a fix is applied.