CVE-2026-54891
MediumCVSS 6.3Exploitation Probability (EPSS)
Low risk6th percentile — higher than 6% of all known CVEs
Summary
A vulnerability in the Erlang/OTP SSL library (tls_gen_connection module) involves improper enforcement of message integrity during transmission. A network attacker can inject unauthenticated plaintext to a TLS client during the handshake, which after completion is treated by the application as authenticated server data.
Risk Assessment
The risk is that an attacker can inject unauthenticated data into the TLS client's communication stream, potentially compromising data integrity and being used by the application as trusted information. The attack is limited to blind byte injection without the ability to observe the client's response.
Recommendation
Immediately update Erlang/OTP to version 29.0.3, 28.5.0.3, or 27.3.4.14 (depending on the branch) and the corresponding ssl library to version 11.7.3, 11.6.0.3, or 11.2.12.10. For TLS 1.3, update from OTP 22.0 onwards.
Original NVD description (English source)
Improper Enforcement of Message Integrity During Transmission in a Communication Channel vulnerability in Erlang/OTP ssl (tls_gen_connection module) allows a network-positioned attacker to inject unauthenticated plaintext that the TLS client application later treats as authenticated server data. The function tls_gen_connection:handle_protocol_record/3 rejects APPLICATION_DATA records that arrive in pre-handshake states when the TLS endpoint acts as a server, but does not apply the same check when the endpoint acts as a client. A network-positioned attacker can send plaintext APPLICATION_DATA records to the client during the handshake. The records are buffered and, once the handshake completes successfully, delivered to the application as if they were authenticated post-handshake data. The attacker cannot observe the client's response or steer the connection, so the impact is limited to blind injection of unauthenticated bytes. The injection window is wider for TLS versions prior to TLS 1.3 than for TLS 1.3. This vulnerability is associated with program file lib/ssl/src/tls_gen_connection.erl. This issue affects OTP from OTP 17.0 before 29.0.3, 28.5.0.3 and 27.3.4.14 corresponding to ssl from 5.3.4 before 11.7.3, 11.6.0.3 and 11.2.12.10. TLS 1.3 is affected starting with OTP 22.0, when TLS 1.3 support was added.