CVE-2026-44236

Overview

The rabbitmq-c client library prior to version 0.16.0 contains a heap memory corruption vulnerability during the AMQP login process. A malicious or compromised server, as well as an on-path attacker intercepting plaintext traffic, can supply an undersized frame_max value. This causes subsequent buffer reallocations to write out-of-bounds, leading to a denial of service.

Description

rabbitmq-c is a C-language AMQP client library for RabbitMQ. Prior to 0.16.0, a malicious AMQP server can send an undersized connection.tune.frame_max value during amqp_login(), and rabbitmq-c accepts the value in amqp_login_inner() in librabbitmq/amqp_socket.c. amqp_tune_connection() in librabbitmq/amqp_connection.c uses frame_max to reallocate the outbound buffer without enforcing AMQP_FRAME_MIN_SIZE. Immediate serialization of connection.tune-ok through amqp_frame_to_bytes() writes beyond the undersized heap allocation, causing memory corruption and likely denial of service. An on-path attacker can also trigger the flaw against plaintext AMQP traffic. Code execution is theoretically possible but was not demonstrated. This issue is fixed in version 0.16.0.

Impact

This vulnerability impacts the integrity and availability of applications utilizing the rabbitmq-c library. Successful exploitation results in memory corruption and application crashes, leading to a denial of service. While remote code execution is theoretically possible, it has not been demonstrated.

Remediation

Upgrade the rabbitmq-c library to version 0.16.0 or later where minimum frame size validation is enforced. Additionally, ensure that AMQP communications are encrypted using TLS to protect against on-path attackers manipulating traffic in transit.

Risk context

Rated with a high severity score (CVSS 7.1), this vulnerability requires immediate attention for systems that communicate with untrusted AMQP servers or operate over unencrypted networks.

Affected products

• rabbitmq-c < 0.16.0