Summary A vulnerability exists in the amqp091-go client library where a compromised or malicious AMQP broker can force the client to allocate resources for and process content body frames that exceed the negotiated framemax limit. This can lead to unexpected memory consumption or application-layer denial of service (DoS), bypassing the protocol's built-in framing constraints.

Details During a standard AMQP 0-9-1 connection handshake, the client and the broker negotiate a maximum frame size (framemax), for example, 4096 bytes.

However, after negotiation, a malicious broker can send a valid basic.deliver sequence containing a content body frame whose header declares a payload size larger than the negotiated framemax. Instead of enforcing the agreed-upon limit and closing the connection with a frame-error (as mandated by the AMQP 0-9-1 specification), the amqp091-go client:

1. Accepts the broker-declared oversized frame size. 2. Allocates memory based on this oversized declaration. 3. Reads the payload, assembles it into the message, and delivers it to the consumer.

Impact

- Denial of Service (DoS): If a broker sends extremely large frame sizes, it can trigger significant memory allocations on the client side, potentially leading to Out-Of-Memory (OOM) crashes. - Protocol Violation: The client fails to enforce negotiated connection parameters, trusting the broker implicitly even after constraints have been established.

RabbitMQ amqp091-go is a Go AMQP 0.9.1 client. Prior to 1.13.0, the writeShortstr function in write.go casts the byte length of AMQP shortstr property values to uint8 without first rejecting values longer than 255 bytes. An application that accepts an oversized CorrelationId, ReplyTo, MessageId, Expiration, UserId, AppId, ContentType, ContentEncoding, or Type value can therefore serialize a wrapped length and only a truncated prefix, while reporting no error. The resulting silent metadata corruption can break request and reply correlation, routing, tracing, and downstream message processing. This issue is fixed in version 1.13.0.

RabbitMQ amqp091-go is a Go AMQP 0.9.1 client. Prior to 1.13.0, PlainAuth values defined in auth.go retain passwords as exported plaintext fields in Connection.Config.SASL after a successful PLAIN authentication handshake. The Connection.openComplete method in connection.go does not clear those values. Code with access to the Connection object, including reflective loggers, application performance monitoring agents, debugging utilities, and panic handlers, can traverse the configuration and expose the credentials to logs or state captures. The credential remains available for the lifetime of the connection instead of being cleared after authentication. This issue is fixed in version 1.13.0.

RabbitMQ amqp091-go is a Go AMQP 0.9.1 client. Prior to 1.13.0, URI.String in uri.go concatenates CertFile, KeyFile, CACertFile, and ServerName values directly into an AMQPS query string instead of encoding them as URL query parameters with url.Values. If an application accepts a TLS asset path containing ampersand or equals delimiters and later reparses the serialized URI with ParseURI, the embedded delimiters can create or overwrite connection options, including paths to TLS certificate, key, or CA files. This can corrupt connection configuration or select unintended local cryptographic assets. This issue is fixed in version 1.13.0.

RabbitMQ amqp091-go is a Go AMQP 0.9.1 client. Prior to 1.13.0, Channel.Qos in channel.go accepts negative prefetchCount and prefetchSize integers and casts them directly to uint16 and uint32 fields in the basic.qos method because validateQos is absent. Values such as -1 therefore wrap to 65535 or 4294967295 instead of being rejected. An application that permits untrusted configuration of these Qos values can unintentionally request extremely large prefetch limits, allowing a broker to deliver enough queued messages to exhaust client memory and disrupt processing. This issue is fixed in version 1.13.0.

RabbitMQ amqp091-go is a Go AMQP 0.9.1 client. Prior to 1.13.0, readLongstr in read.go returns an empty string and a nil error when a declared AMQP longstr length exceeds 0x7FFFFFFF instead of returning ErrSyntax. The function leaves the declared field bytes unread, while readTable treats the operation as successful and continues parsing from the wrong offset. A malicious or compromised broker can provide an oversized longstr in a table field and desynchronize subsequent AMQP parsing, causing attacker-controlled trailing bytes to be interpreted as later fields or frames and disrupting connection integrity and availability. This issue is fixed in version 1.13.0.

RabbitMQ amqp091-go is a Go AMQP 0.9.1 client. Prior to 1.13.0, readField in read.go reads the length of an AMQP byte-array field with type tag x into a signed int32 and passes the value directly to make when allocating the field buffer. A malicious or compromised broker can encode a value such as 0xFFFFFFFF, which becomes -1 and causes a len out of range runtime panic. The panic escapes the network reader goroutine and terminates the client process, including during connection.start server properties or message header table parsing. This issue is fixed in version 1.13.0.