CVE-2026-67219: Rabbitmq Rabbitmq-Server

Medium severity, CVSS 6.0. EPSS: 0.3% chance of exploitation in the next 30 days.

RabbitMQ is a messaging and streaming broker. Prior to versions 3.13.15, 4.0.20, 4.1.11, 4.2.6, and 4.3.0, add_binding/3 parses the routing key as an integer weight N and computes ring positions with lists:seq(NextN0, NextN0 + N - 1). validate_binding/2 only checks N >= 1 , no upper bound. The resulting list is stored in the exchange's Khepri record, replicated cluster-wide, and reloaded on restart. A user with write permission on a consistent-hash exchange and read on a queue can create a binding whose routing key (the hash-ring weight) is an arbitrarily large integer. The broker allocates a list of that many integers via lists:seq/2 and persists it to Khepri across all cluster nodes , a single binding with weight 100000000 allocates ~800 MB on every node and survives restarts. Preconditions include rabbitmq_consistent_hash_exchange plugin enabled write permission on a consistent-hash exchange + read on a queue (standard binding perms). This issue is fixed in versions 3.13.15, 4.0.20, 4.1.11, 4.2.6, and 4.3.0.

Affected products

• Rabbitmq Rabbitmq-Server: from 3.13.0, before 3.13.15 (fixed in 3.13.15); from 4.0.0, before 4.0.20 (fixed in 4.0.20); from 4.1.0, before 4.1.11 (fixed in 4.1.11); from 4.2.0, before 4.2.6 (fixed in 4.2.6)

Published 2026-09-23. Last modified 2026-09-24.