Key Exchange without Entity Authentication in Erlang OTP - CVE-2026-89422
Published: October 14, 2026
Vulnerability details
The vulnerability allows a remote attacker to impersonate TLS servers, disclose sensitive information, and forge application responses.
The vulnerability exists due to key exchange without server authentication in the Erlang/OTP ssl application's TLS 1.3 client when processing a ServerHello containing a pre_shared_key extension that the client never offered. A remote attacker can send this unsolicited extension and a Finished message computed using its own ephemeral ECDHE key to impersonate TLS servers, disclose sensitive information, and forge application responses.
Exploitation requires a malicious host that the client connects to or an on-path peer able to answer the connection. The issue occurs even with verify_peer and trusted CA certificates configured. No certificate, private key, or prior session is needed. Clients restricted to TLS 1.2 are not affected.