OCTOBER 7, 2026
Live Feed
Back to database
Case File

CVE-2026-89422

CRITICAL · CVSS 9.3 EPSS 0.46% Public Exploit

Source: NVD + CISA KEV + EPSS · Published 2026-09-22 · Last synced 2026-10-07

CyberRota Analysis

AI-Generated

A critical vulnerability in the Erlang/OTP ssl component allows an attacker to impersonate a legitimate server during a TLS 1.3 handshake, bypassing essential certificate validation checks. This flaw affects Exchange products using vulnerable versions of OTP, enabling unauthorized access to sensitive data and potentially compromising the integrity of communications. Organizations utilizing these affected versions should prioritize immediate updates to mitigate the risk of exploitation.

Public Exploit Signal

A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.

Note: these links are listed for security research and verification purposes only.

CVE
CVE-2026-89422
Severity
CRITICAL
CVSS
9.3
EPSS
0.46%
Exchange

Original NVD Description

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.