Copyright © 2012 Red Hat, Inc. All rights reserved. Important 2026-07-02T16:06:08 erlang: Erlang/OTP: Denial of Service in TLS 1.3 session ticket handling 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H CWE-130

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 OTP 22.2 before OTP 29.0.3, OTP 28.5.0.3 and OTP 27.3.4.14, corresponding to ssl from 9.5 before 11.7.3, 11.6.0.3 and 11.2.12.10.

A flaw was found in Erlang/OTP's SSL (Secure Sockets Layer) application. An unauthenticated remote attacker can send a specially crafted ClientHello message to a TLS 1.3 server with session tickets enabled. This can permanently disrupt the server's ability to handle session tickets, leading to a Denial of Service (DoS) for new TLS 1.3 connections until the SSL application is restarted. This vulnerability is caused by improper validation of PSK (Pre-Shared Key) identity and binder list lengths.

A flaw was found in the Erlang/OTP ssl application. The TLS 1.3 session ticket handler does not validate that PSK identity and binder lists have equal length, allowing an unauthenticated attacker to crash session ticket handling via a crafted ClientHello, making TLS 1.3 unusable until the ssl application is restarted. Restarting the ssl application restores TLS 1.3 functionality after a crash. TLS 1.2 connections are not affected. Disabling TLS 1.3 session tickets (stateful and stateless) eliminates the attack surface. Red Hat OpenStack Platform 16.2 Affected erlang Red Hat OpenStack Platform 17.1 Affected erlang Red Hat OpenStack Platform 18.0 Affected erlang https://www.cve.org/CVERecord?id=CVE-2026-55952 https://nvd.nist.gov/vuln/detail/CVE-2026-55952 https://cna.erlef.org/cves/CVE-2026-55952.html https://github.com/erlang/otp/commit/2c3e599797644310e5d4aa39c7193420e59dadff https://github.com/erlang/otp/commit/9b5437c72fa3403a75c1aba28e5c532bc191c662 https://github.com/erlang/otp/commit/e77823e6d980b2ec0b4fe4ea3f2d098ca239e3ce https://github.com/erlang/otp/security/advisories/GHSA-8c57-44c9-pc59 https://osv.dev/vulnerability/EEF-CVE-2026-55952 https://www.erlang.org/doc/system/versions.html#order-of-versions