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Miggo AIRoot Cause AnalysisThe vulnerability, CVE-2026-77412, is a Denial of Service (DoS) in the rabbitmq/amqp091-go client library. It stems from improper handling of a negative length value when parsing AMQP byte-array fields. The readField function, specifically the code block handling the 'x' type tag, reads a 32-bit big-endian integer to determine the length of a byte array. If a malicious AMQP server sends 0xFFFFFFFF as this length, it is interpreted as -1 by the client's signed 32-bit integer type. Subsequently, this negative length is passed to Go's built-in make([]byte, len) function, which panics when given a negative length, leading to an unhandled runtime error and crashing the client application. The patch introduces a check if len < 0 { return nil, ErrSyntax } immediately before the make call, preventing the negative length from being used and thus mitigating the DoS. Therefore, readField is the precise function where the vulnerability resides and would appear in a stack trace during exploitation.
readFieldread.go
| Package Name | Ecosystem | Vulnerable Versions | First Patched Version |
|---|---|---|---|
| github.com/rabbitmq/amqp091-go | go | < 1.13.0 | 1.13.0 |