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CVE-2026-89422 Affecting erlang package, versions *

Severity

 Recommended
medium

Based on Ubuntu security rating.

Threat Intelligence

EPSS
0.46% (38th percentile)

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  • Snyk IDSNYK-UBUNTU2004-ERLANG-20047118
  • published7 Oct 2026
  • disclosed22 Sept 2026
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Introduced: 22 Sep 2026

NewCVE-2026-89422  (opens in a new tab)

How to fix?

There is no fixed version for Ubuntu:20.04 erlang.

NVD Description

Note: Versions mentioned in the description apply only to the upstream erlang package and not the erlang package as distributed by Ubuntu. See How to fix? for Ubuntu:20.04 relevant fixed versions and status.

Key Exchange without Entity Authentication vulnerability in Erlang/OTP ssl allows a peer that answers a TLS 1.3 client connection to impersonate the intended server. A pre_shared_key extension in the ServerHello that the client never offered causes the client to complete the handshake without validating the server's certificate, so ssl:connect returns {ok, Socket} against a peer holding no certificate, no private key and no prior session.

tls_client_connection_1_3:handle_server_hello/2 passes the received extension to tls_gen_connection_1_3:handle_resumption/2, which sets resumption = true on its mere presence without checking that the client offered a PSK. tls_handshake_1_3:get_pre_shared_key/4 meanwhile falls back to the all-zero "no PSK" value and keys the handshake with the ordinary non-PSK schedule, so the attacker's own ephemeral key suffices. The resumption flag then routes maybe_resumption/1 straight to wait_finished, skipping the certificate-handling states, so certificate path validation, verify_fun, hostname verification, partial_chain, CRL checking and OCSP stapling are all bypassed. The default client configuration is affected; clients restricted to TLS 1.2 are not.

This issue affects OTP from OTP 22.2 before OTP 27.3.4.18, OTP 28.5.0.7, and OTP 29.1.1, corresponding to ssl from 9.5 before 11.2.12.13, 11.6.0.6, and 11.7.7.