Rustls 0.23.13 before 0.23.45 TLS 1.3 Handshake Encryption Level Bypass

Rustls from 0.23.13 before 0.23.45 accepts TLS 1.3 handshake messages at the wrong encryption level when they follow a key-changing message in the same record, because Deframer::aligned does not enforce RFC 8446 record-boundary alignment. A peer or on-path attacker can pack a plaintext EncryptedExtensions with the ServerHello, which rustls accepts unencrypted.

Rustls before 0.23.46 and 0.24.0-dev.1 before 0.24.0-dev.2 Secret Exposure via Debug

Rustls before 0.23.46 and 0.24.0-dev.1 before 0.24.0-dev.2 contains an information disclosure vulnerability where derived Debug formatting of client session values exposes secret key material. Custom ClientSessionStore implementations that log Tls12ClientSessionValue or Tls13ClientSessionValue can leak TLS 1.2 master secrets or TLS 1.3 resumption PSKs to log readers.

rustls before 0.23.46 Denial of Service via Brotli Certificate Decompression

rustls before 0.23.46 contains an uncontrolled memory allocation flaw in its optional Brotli certificate decompression, which limits decompressed output size but accepts an input-selected large history window. Malicious peers can send a certificate with a five-byte Brotli header requesting up to 1 GiB before authentication, aborting Brotli-enabled clients or client-authenticating servers whose allocator cannot satisfy the request.

rustls before 0.23.46 Key Exchange Downgrade via Unauthenticated ServerHello

rustls before 0.23.46 contains a key exchange downgrade vulnerability that allows network attackers to poison the per-server-name key-exchange group record via an unauthenticated ServerHello. Attackers can answer one connection with a ServerHello selecting X25519, causing later ClientHellos to send only classical shares and lose post-quantum confidentiality.

rustls 0.23.44 and 0.23.45 ECH Rejection Application Data Disclosure

rustls 0.23.44 and 0.23.45 contain an information disclosure vulnerability that sends application data buffered before the handshake completes to the client-facing server when Encrypted Client Hello is rejected. Because start_traffic() queues plaintext from ClientConnection::writer() before sending the ech_required alert, the authenticated public_name server receives data intended for the inner server.

Rustls vulnerable to an infinite loop in rustls::conn::ConnectionCommon::complete_io() with proper client input

Rustls is a modern TLS library written in Rust. `rustls::ConnectionCommon::complete_io` could fall into an infinite loop based on network input. When using a blocking rustls server, if a client send a `close_notify` message immediately after `client_hello`, the server's `complete_io` will get in an infinite loop. This vulnerability is fixed in 0.23.5, 0.22.4, and 0.21.11.

Rustls: rustls network-reachable panic in `acceptor::accept`

A flaw was found in Rustls 0.23.13 and related APIs. This vulnerability allows denial of service (panic) via a fragmented TLS ClientHello message.

rustls-mio/examples/tlsserver.rs in the rustls crate before 0.16.0 for Rust allows attackers to cause a denial of service (loop of conn_event and ready) by arranging for a client to never be writable.