Junglewise Threat Intelligence

CVE-2026-55952: Erlang OTP denial of service in SSL TLS 1.3 session ticket handling

CVE-2026-55952 · Severity: info · CVSS 8.2 · Published 2026-07-02

Technologies: Erlang OTP, Erlang Ssl. Vendors: Erlang.

Executive brief

A vulnerability in the Erlang/OTP SSL library can allow a remote attacker to crash the component responsible for handling secure session tickets. By sending a specially crafted connection request, an attacker can permanently disrupt the server's ability to process new TLS 1.3 connections that use session tickets. This results in a denial-of-service condition for secure web traffic until the affected application is manually restarted.

Technical details

A denial-of-service vulnerability exists in the Erlang/OTP ssl application due to improper validation of the Pre-Shared Key (PSK) extension in TLS 1.3. Specifically, the function 'tls_handshake_1_3:handle_pre_shared_key/3' does not verify that the PSK identity list and binder list have equal lengths. An unauthenticated remote attacker can exploit this by sending a crafted ClientHello with mismatched list lengths, causing the 'tls_server_session_ticket' process to crash. This permanently disrupts session ticket handling on the affected listener until a restart. The issue is fixed in OTP versions 29.0.3, 28.5.0.3, and 27.3.4.14.

Affected products

  • Erlang OTP 22.2 before 29.0.3, 28.5.0.3, and 27.3.4.14
  • Erlang ssl 9.5 before 11.7.3, 11.6.0.3, and 11.2.12.10

Timeline

  • 2026-07-02: advisory
  • 2026-07-02: disclosed

References

Related threats