Bug 2552615 (CVE-2026-94200)

Summary: CVE-2026-94200 erlang: Erlang: Denial of Service via malformed TLS 1.3 session ticket
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Version: unspecifiedKeywords: Security
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OS: Linux   
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A flaw was found in Erlang's SSL application. A malicious Transport Layer Security (TLS) server can cause a Denial of Service (DoS) across client connections by returning an improperly formatted session resumption ticket with an empty early data extension. When the client attempts to automatically resume the session, the malformed ticket triggers an unhandled error in the ticket store, causing it to crash. Repeated crashes exceed internal supervisor restart limits, resulting in the termination of the SSL service and disrupting all secure connections on the client node.
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Description OSIDB Bzimport 2026-10-14 17:28:49 UTC
Improper Validation of Consistency within Input vulnerability in Erlang OTP ssl (tls_handshake_1_3, ssl_handshake and tls_client_ticket_store modules) allows a malicious TLS 1.3 server to cause a denial of service of the ssl application on the client node.

The TLS 1.3 client decodes the extensions of a NewSessionTicket message as if they came from EncryptedExtensions. It therefore accepts a 0-length early_data extension, a form that is only valid in ClientHello and EncryptedExtensions. With {session_tickets, auto}, the client stores the ticket in the node-global tls_client_ticket_store. On the next automatic resumption, tls_handshake_1_3:get_max_early_data/1 crashes the store with a case_clause. Repeated crashes can exceed the restart intensity of the ssl supervisors, which use the rest_for_one strategy, and take down ssl for all connections on the node.

This issue affects OTP from OTP 23.3 before OTP 27.3.4.19, OTP 28.5.0.8, and OTP 29.1.2, corresponding to ssl from 10.3 before 11.2.12.14, 11.6.0.7, and 11.7.8.