CVE-2026-55952
HighCVSS 8.2Exploitation Probability (EPSS)
Low risk37th percentile — higher than 37% of all known CVEs
Summary
A vulnerability in the Erlang/OTP ssl application allows an unauthenticated attacker to permanently disrupt TLS 1.3 session ticket handling by sending a crafted ClientHello with mismatched PSK identity and binder lists. This crashes the session ticket handler process, making TLS 1.3 unusable on the affected listener until the ssl application is restarted.
Risk Assessment
An attacker can remotely and without authentication permanently disable TLS 1.3 on the server, causing service disruption for clients using this protocol version. TLS 1.2 remains unaffected, but the organization loses support for newer, more secure connections.
Recommendation
Immediately upgrade Erlang/OTP to version 29.0.3, 28.5.0.3, or 27.3.4.14 (or later) and the corresponding ssl application to version 11.7.3, 11.6.0.3, or 11.2.12.10. If upgrading is not possible, temporarily disable TLS 1.3 session ticket support.
Original NVD description (English source)
The Erlang/OTP ssl application does not validate that the PSK identity list and binder list carried in a TLS 1.3 ClientHello pre-shared key extension have equal length before passing them to the session ticket handler. In tls_handshake_1_3:handle_pre_shared_key/3, an OfferedPreSharedKeys record with a mismatched number of identities and binders is forwarded directly to tls_server_session_ticket:use/4, which crashes the session ticket handler process. An unauthenticated remote attacker can send a single crafted ClientHello to a TLS 1.3 server with session tickets enabled (stateful or stateless mode) and permanently disrupt session ticket handling on that listener. New TLS 1.3 handshakes complete but subsequently crash when the server attempts to issue a session ticket, effectively making TLS 1.3 unusable on the affected listener until the ssl application is restarted. TLS 1.2 connections are not affected. This issue affects OTP from 22.2 before 29.0.3, 28.5.0.3 and 27.3.4.14 corresponding to ssl from 9.5 before 11.7.3, 11.6.0.3 and 11.2.12.10.