CVE-2026-55952

Summary

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.

Affected Software

VendorProductVersion RangeStatus
ErlangOTP9.5 < *affected
ErlangOTP22.2 < *affected
ErlangOTP339a279f02ce38a7b23010e56000613e19abb21f < *affected

Weaknesses

  • CWE-1284: CWE-1284 Improper Validation of Specified Quantity in Input

Workarounds

  • Disable session tickets on TLS 1.3 servers by setting session_tickets to disabled in the server's ssl options.
  • Restrict the server to TLS 1.2 by setting versions to ['tlsv1.2'] in the server's ssl options.

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: partial

References