CVE-2026-77406 RabbitMQ amqp091-go: Consumer Message Flooding via Signed-to-Unsigned Integer Casting in Qos Configuration
An attacker with control over Qos configuration can cause memory exhaustion and denial of service in applications using the RabbitMQ Go client.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-77406?
CVE-2026-77406 is a high-severity vulnerability in rabbitmq amqp091-go, published on 16 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Weakness: CWE-195
Which versions are affected by CVE-2026-77406?
3 open source packages ship an affected version, including github.com/rabbitmq/amqp091-go.
| Package | Affected | Fixed in |
|---|---|---|
github.com/rabbitmq/amqp091-go Go | All versions | 1.13.0 |
github.com/rabbitmq/amqp091-go Go | All versions | 1.13.0 |
github.com/rabbitmq/amqp091-go Go | All versions | 1.13.0 |
How do I fix CVE-2026-77406?
Upgrade github.com/rabbitmq/amqp091-go to 1.13.0 or later.
Is CVE-2026-77406 being exploited?
There is no known exploitation of CVE-2026-77406 in the wild and no public exploit code.
Sources
Also known as AZL-103188, AZL-103287, CLEANSTART-2026-KU86839, CLEANSTART-2026-QW84493, CLEANSTART-2026-VO07042, DEBIAN-CVE-2026-77406 and 41 more.