CVE-2026-55952 Details

A denial-of-service vulnerability has been identified in the Erlang/OTP SSL application, specifically in versions 22.2 prior to 29.0.3, 28.5.0.3, and 27.3.4.14. The issue arises in the TLS 1.3 ClientHello pre-shared key extension, where the application fails to validate that the lengths of the PSK identity list and binder list are equal before forwarding them to the session ticket handler. This flaw allows an unauthenticated remote attacker to send a crafted ClientHello to a TLS 1.3 server with session tickets enabled, either in stateful or stateless mode. The malformed ClientHello disrupts session ticket handling on the affected listener, causing new TLS 1.3 handshakes to crash when the server attempts to issue a session ticket. As a result, TLS 1.3 becomes unusable on the affected listener until the SSL application is restarted. Notably, TLS 1.2 connections are not affected.

Users can upgrade to Erlang/OTP versions 29.0.3, 28.5.0.3, or 27.3.4.14 to address this vulnerability. Alternatively, session tickets can be disabled on TLS 1.3 servers by setting the session_tickets option to disabled, or the server can be restricted to TLS 1.2 by setting the versions option to ['tlsv1.2'].