The max body size was enforced to patch CVE-2023-46120, but even though that limit still works, the frame size itself still exceeds the given max size.
The Java client records the AMQP 0-9-1 frame_max negotiated during connection tuning, but the socket inbound frame reader continues to validate broker-controlled payload lengths against the much larger maxInboundMessageBodySize limit. A broker peer can therefore send a method frame whose payload is larger than the negotiated frame_max, have it allocated and decoded, and complete the connection handshake instead of being rejected as a protocol violation.
Reported by Team Atlanta.
{
"cwe_ids": [
"CWE-20"
],
"github_reviewed": true,
"github_reviewed_at": "2026-08-18T16:36:29Z",
"nvd_published_at": null,
"severity": "LOW"
}