CVE-2026-94200

Deferred Deferred - Pending Action

Denial of Service in Erlang OTP ssl

Publication date: 2026-10-14

Last updated on: 2026-10-16

Assigner: EEF

Description

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.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-10-14

Last Modified

2026-10-16

Generated

2026-10-19

AI Q&A

2026-10-15

EPSS Evaluated

2026-10-18

NVD

CVE-2026-94200

EUVD

EUVD-2026-101384

Affected Vendors & Products

Vendor	Product	Version / Range
Erlang	OTP	23.3
Erlang	OTP	10.3
Erlang	OTP	0abe6f66db0d295cd06b0efab3bdb3caa2803930

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-1288	The product receives a complex input with multiple elements or fields that must be consistent with each other, but it does not validate or incorrectly validates that the input is actually consistent.

Attack-Flow Graph

Executive Summary

This vulnerability is an Improper Validation of Consistency within Input issue in Erlang OTP's SSL application. A malicious TLS 1.3 server can exploit it by sending a poisoned NewSessionTicket message with a zero-length early_data extension. The client incorrectly decodes this as if it came from EncryptedExtensions, causing the tls_client_ticket_store to crash during session resumption. Repeated crashes can exceed supervisor restart limits, taking down the entire SSL service on the node.

Detection Guidance

Detecting this vulnerability requires checking the Erlang/OTP version and SSL application version on your system. Use commands like 'erl -version' to check OTP version and 'application:which_applications().' in an Erlang shell to verify ssl application version. If your versions are below 27.3.4.19, 28.5.0.8, or 29.1.2, you are vulnerable.

Impact Analysis

The primary impact is a denial of service where the SSL service crashes and becomes unavailable on the affected node. This disrupts all TLS connections on that node, potentially causing service outages for applications relying on secure communications. The attack requires network access but no privileges or user interaction.

Compliance Impact

This vulnerability primarily impacts system availability by causing denial-of-service conditions in TLS 1.3 clients. While it does not directly affect data confidentiality or integrity, prolonged outages could interfere with logging, monitoring, or secure communication required by GDPR and HIPAA. Compliance may be indirectly impacted if availability requirements are not met due to service disruptions.

Mitigation Strategies

Upgrade Erlang/OTP to a patched version (27.3.4.19, 28.5.0.8, or 29.1.2) or ssl application to 11.7.8, 11.6.0.7, or 11.2.12.14.
If upgrading is not immediately possible, disable automated session ticket handling by setting {session_tickets, manual} or {session_tickets, disable} in your SSL configuration.

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