Summary

A critical stream desynchronization vulnerability has been identified in the AMQP wire-protocol parser. When parsing a long string (readLongstr) within a table field, providing a length that exceeds the maximum signed 32-bit integer (2^31 - 1, or roughly 2.1 GiB) triggers an improper error-handling condition. The parser abruptly aborts the read and returns a success status ("",nil) without consuming the specified bytes from the underlying network buffer. This causes all subsequent read operations to become misaligned. The parser interprets arbitrary offsets within the remaining payload bytes as valid AMQP frame headers, leading to potential Remote Code Execution (RCE), data injection, or complete connection hijacking.

Vulnerability Details

The vulnerability exists within the bounds-checking logic of the readLongstr function: go // read.go:113-114 — silent no-op return, bytes left in stream if length > (^uint32(0) >> 1) { return // returns "", nil, does NOT consume length bytes } When length evaluates to a value greater than 0x7FFFFFFF:

1. The function executes a silent return statement. 2. Because Go utilizes named or zero-value initialization for unassigned return registers, this yields "", nil (indicating a successful read of an empty string). 3. The Critical Failure: The reader's cursor is not advanced by length bytes. The malformed payload remains sitting in the TCP/buffer stream.

Impact

As readTable continues iterating over the stream under the assumption that the string was successfully parsed, the byte alignment is entirely broken.

- Parser Desynchronization: Future AMQP frame headers are read from arbitrary offsets inside the attacker-controlled message payload. - Payload Reinterpretation: A malicious actor can carefully craft the trailing bytes of the initial payload to perfectly mimic valid AMQP frames (e.g., connection.close, channel.open, or message publishing frames), forcing the client/server to execute unintended actions.

Summary A data integrity and protocol corruption vulnerability exists in the AMQP client's property serialization logic. When encoding AMQP short string (shortstr) fields—such as identifiers, routing strings, and content metadata—the length of the string is explicitly cast to a fixed-size 8-bit unsigned integer (uint8).

If an application provides a property string exceeding 255 bytes, the length counter silently wraps around (e.g., a length of 300 wraps to 44). As a result, the parser writes only a truncated portion of the string into the outgoing connection buffer without returning an error. This leads to silent data corruption, broken RPC routing, and unpredictable broker-side state behavior.

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Vulnerability Details

Mechanism The vulnerability resides in the wire-level serialization logic for application publishing properties:

go // write.go:246 length := uint8(len(b)) // wraps silently when len(b) > 255 (e.g., 300 -> 44)

Because Go allows silent integer truncation during explicit type casting, lengths larger than $2^8 - 1$ lose their most significant bits. The underlying stream writer reads length to determine how many bytes to pull from the buffer. Because no error or boundary check accompanies this truncation, the application believes the full payload was transmitted successfully.

Affected Properties This truncation behavior affects every standard AMQP field serialized as a shortstr: CorrelationId ReplyTo MessageId Expiration UserId AppId ContentType ContentEncoding Type

Impact The critical consequence is silent protocol desynchronization at the application layer. The underlying TCP stream remains framed properly (because the shortened length matches the bytes written), but the business logic is corrupted. Distributed transactions, request-reply correlations, and tracing headers are truncated, causing downstream systems to drop messages or route them to incorrect consumers.

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Attack Vector An attacker who can influence metadata fields processed by an upstream application (such as a user-supplied tracking ID or a long content-type header) can exploit this to break system components:

1. Targeting RPC Routing: A user passes a malicious or overly long CorrelationId of 300 bytes through an application endpoint. 2. Silent Truncation: The library wraps the length value to 44, transmitting only the first 44 bytes to the rabbitMQ broker. 3. Broken Correlation: When the service processes the request and responds, the replying consumer attempts to route the message using the full 300-byte identifier. Because the broker only recognizes the truncated 44-byte ID, the reply loop breaks silently, leading to hanging processes or data leaks across transaction boundaries.

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.

Summary A vulnerability in the readField function allows a malicious or compromised AMQP server to trigger an unhandled runtime panic in the client application, leading to an immediate crash of the entire process.

Details When parsing incoming AMQP frames, the readField function processes byte-array fields (type tag 'x') by reading a 32-bit big-endian integer to determine the length of the data payload.

go // read.go:253-263 case 'x': var len int32 if err = binary.Read(r, binary.BigEndian, &len); err != nil { return nil, err } value := make([]byte, len) // PANICS if len < 0

If a server transmits a length value of 0xFFFFFFFF, it is interpreted by the client as a signed 32-bit integer with a value of -1. Passing a negative integer to Go's built-in make() function for slice allocation triggers an unrecoverable runtime panic (panic: len out of range).

Because the reader goroutine handles network I/O without an explicit recover() wrapper, this panic propagates up to the runtime root, abruptly terminating the host application.

Attack Vector / Exploitation Scenario An attacker capable of spoofing, compromising, or controlling an AMQP broker can exploit this flaw during two primary phases:

1. Connection Establishment: Sending a malicious connection.start handshake frame containing server-properties with an 'x' type field assigned a negative length. 2. Message Delivery: Delivering a message payload where the header table contains a malformed field matching the criteria above.

Impact Availability: High. A single malformed frame can reliably crash the client process, resulting in a persistent Denial of Service (DoS) if the client automatically reconnects and receives the same payload.

Summary A query parameter injection vulnerability exists in the AMQP client's connection URI formatting logic. When generating or parsing connection URIs, TLS-related filesystem paths (such as certificates or keys) are appended directly to the URI's query string using string concatenation rather than secure URL encoding via functions like url.QueryEscape.

If an application handles a TLS file path containing special character delimiters (such as & or =), these characters are interpreted as parameter separators by the URI parser. If the resulting URI.String() output is subsequently re-parsed via ParseURI, the injected fields can silently overwrite or hijack critical configuration parameters, forcing the client to use arbitrary connection settings or alternate TLS files.

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Vulnerability Details

Mechanism The vulnerability lies within the lack of proper escaping when compiling connection string components into a raw URL format:

go // Example of insecure string concatenation during URI building uri := fmt.Sprintf("amqps://user:pass@host/%s?certfile=%s&keyfile=%s", vhost, certPath, keyPath)

Because certPath and keyPath are not passed through url.QueryEscape, special URL characters preserve their control meanings. For instance, if a user supply a certificate path named: /tmp/cert=foo&keyfile=/evil/path

The generated string translates into: ...?certfile=/tmp/cert=foo&keyfile=/evil/path&keyfile=/original/path

When this string passes back through ParseURI (common in connection re-dial routines or configuration replication steps), standard URL parsing mechanics treat the string as multiple distinct parameters. Depending on map assignment order inside the parser, the injected keys take precedence over the original parameters.

Impact By manipulating the file paths used for TLS assets, an attacker or compromised local sub-system can: Inject arbitrary alternative options or override protocol settings. Substitute or switch keyfiles, leading to connection failures or the parsing of unauthorized cryptographic assets. Corrupt connection state variables, triggering application-layer failures during connection setup or recovery.

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Attack Vector An attacker who has partial control over directory naming conventions or environmental variables used to specify local infrastructure paths can execute a parameter injection attack:

1. Path Creation: An attacker sets up a path containing deliberate URL parameter delimiters (e.g., /var/lib/certs/client.crt?cacertfile=/tmp/fakeca.crt&). 2. String Generation: The application serializes the active connection state or passes the paths down to an unescaped URI builder function. 3. Configuration Hijack: The URI string is generated with the injected parameter embedded into the query structure. When the client attempts to reuse or re-parse this connection string during a connection retry or worker spin-up, it parses the injected cacertfile parameter, loading a different, unverified Certificate Authority string.

Summary A logic and resource exhaustion vulnerability exists in the AMQP client's Quality of Service (Qos) configuration method. The Qos function accepts signed integers (int) for the prefetchCount and prefetchSize parameters but casts them directly to unsigned integers (uint16 and uint32, respectively) when formatting the wire-level frame.

If a developer passes a negative integer (such as -1) to these parameters—frequently intended as a sentinel value meaning "no change" or "no limit"—the application performs an implicit signed-to-unsigned conversion. This wraps the values to their absolute maximum limit ($65535$ and $4294967295$). Consequently, a consumer expecting restricted message delivery rates is suddenly flooded with an unlimited volume of messages, potentially exhausting memory resources and crashing the application.

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Vulnerability Details

Mechanism The bug manifests during the structural assignment inside the channel's Qos method:

go // channel.go:795-796 PrefetchCount: uint16(prefetchCount), // -1 wraps to 65535 PrefetchSize: uint32(prefetchSize), // -1 wraps to 4294967295

In Go, converting a negative signed integer to an unsigned integer shifts the value via two's complement arithmetic. Because no boundary validation or signedness check occurs prior to the cast: Passing -1 for prefetchCount yields a wire value of 65535. Passing -1 for prefetchSize yields a wire value of 4294967295.

Impact The AMQP broker interprets a prefetch-count of 65535 as an instruction to dispatch messages to the consumer with virtually no concurrency limits.

If the application is processing heavy payloads or relies on strict rate-limiting to maintain stability, this unexpected flood will cause rapid heap memory growth, unmanageable processing queues, and an eventual Out-Of-Memory (OOM) termination.

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Attack Vector An attacker who can manipulate configuration files, environmental variables, or API inputs that dictate client Qos settings can trigger an application-layer Denial of Service:

1. Malicious Input: An attacker sets a service's prefetch configuration parameter to -1. 2. Implicit Overflow: The application initializes the channel, executes Qos(-1, ...), and transmits an unintended maximum-capacity request to the RabbitMQ/AMQP broker. 3. Consumer Exhaustion: The broker flushes the entire contents of the queue directly into the client consumer's network buffer, bypassing expected application concurrency barriers and inducing a crash.

Summary An information disclosure vulnerability exists in the AMQP client implementation's authentication handling configuration. Following a successful connection handshake, the Connection.Config.SASL field stores the Authentication implementation state used to establish the session.

For standard PLAIN authentication, this state utilizes the PlainAuth struct, which defines both Username and Password as publicly exported, plaintext string fields. Because this sensitive data is retained permanently in-memory within an exported field structure, any peripheral code, internal package, reflective logger, dependency, or automated debugging utility with access to the core Connection object can read and expose the raw credentials.

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Vulnerability Details

Mechanism The vulnerability stems from the structural design of the configuration storage used during and after the AMQP handshake:

go // auth.go:21-23 type PlainAuth struct { Username string Password string // exported plaintext }

When an application initializes a connection, the PlainAuth object is deeply nested inside the configuration structure (Connection.Config). Even after the handshake concludes and authentication is complete, this structure persists natively in-memory for the duration of the network connection's lifecycle.

Because Password is an exported string field, standard automated inspection mechanisms can read its value without restriction.

Affected Code Paths & Integrations Any sub-component or library that traverses or reads the Connection object will inadvertently read the plaintext password, including: Reflective Loggers: Structured logging frameworks that serialize nested configuration structs into JSON/Log formats. APM & Performance Agents: Automated telemetry or Application Performance Monitoring tools that capture state snapshots. Debugging & Panic Handlers: Mid-tier software or dump libraries designed to capture goroutine state or print deep struct hierarchies upon program errors or signals.

Impact The credential remains vulnerable to leak paths into logging pipelines, log aggregators, security information and event management (SIEM) systems, or standard output. Once transmitted to external log infrastructure, these credentials become accessible to unprivileged operators or any actor with access to log archives.

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Attack Vector An attacker does not necessarily need direct remote code execution to exploit this flaw; instead, the vulnerability acts as a credential harvesting vector inside multi-tenant environments or via secondary log exposure:

1. Configuration Dump: An operator configures a standard reflective logger or third-party APM package to capture system state parameters, including the active AMQP Connection object. 2. Reflective Access: The inspection engine uses Go's reflect package to walk the structural hierarchy, pulling the string value from Connection.Config.SASL.(PlainAuth).Password. 3. Exfiltration: The plaintext password is written to standard system logs, which are then scraped into shared logging aggregators, exposing production infrastructure credentials to a wider audience.