CVE-2026-68956: erlang otp

Vulnerability summary

CVE-2026-68956 is a high (CVSS 7.1) vulnerability in erlang otp. EPSS estimates a 0.38% chance of exploitation in the next 30 days, higher than 30.1% of scored vulnerabilities.

Timeline

1. 22-09-2026
   PublishedVulnerability first disclosed.
2. 24-09-2026
   Last modifiedVulnerability information updated.

Description

Allocation of Resources Without Limits or Throttling vulnerability 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 checks only minimal_remote_max_packet_size before calling setup_session/5, which unconditionally builds a #channel{} record and stores it in the ETS channel cache. The max_channels daemon option is consulted only by ssh_channel_sup:max_num_channels_not_exceeded/2, which counts supervisor children, so a channel that never gets a shell, exec, or subsystem handler is invisible to the limit and setting the option to a finite value does not mitigate the attack. RFC 4254 section 5.1 permits many session channels per connection, and each record costs only a few hundred bytes, so a single authenticated connection can accumulate channels until the node runs out of memory and the emulator terminates, affecting every application on it. No file contents, credentials, or write access are obtainable. This issue affects OTP from OTP 18.1.2 before OTP 27.3.4.18, OTP 28.5.0.7, and OTP 29.1.1, corresponding to ssh from 4.1.1 before 5.2.11.13, 5.5.2.6, and 6.0.6. Whether OTP before OTP 18.1.2, corresponding to ssh before 4.1.1, is affected is unknown.

• CWE-770Allocation of Resources Without Limits or ThrottlingThe product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.