Bug 2539780 (CVE-2026-67228)

Summary: CVE-2026-67228 rabbitmq: RabbitMQ: Denial of Service via atom exhaustion in runtime-parameter component
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Priority: medium    
Version: unspecifiedKeywords: Security
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OS: Linux   
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A flaw was found in RabbitMQ. An authorized policymaker can exploit this vulnerability by issuing a large number of requests with distinct component values to the runtime-parameters lookup path. This action coerces attacker-supplied strings into new atoms, eventually exhausting the Erlang atom table. Successful exploitation leads to a denial of service by crashing the RabbitMQ node.
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Description OSIDB Bzimport 2026-09-23 20:52:28 UTC 
RabbitMQ is a messaging and streaming broker. Prior to versions 4.2.7 and 4.3.1, The runtime-parameters lookup path coerces the URL :component segment to an atom with rabbit_data_coercion:to_atom/1 in lookup_component/1 (deps/rabbit/src/rabbit_runtime_parameters.erl), creating a new atom for any previously unseen value. A safe helper, rabbit_registry:binary_to_type/1, which uses binary_to_existing_atom with a catch, already exists but is not used at this call site. lookup_component/1 calls rabbit_data_coercion:to_atom(Component) on the :component segment of the request URL, converting an attacker-supplied string into a new atom. Because the Erlang atom table is bounded and atoms are never garbage collected, an authorized policymaker issuing roughly one million requests with distinct component values can exhaust the atom table and crash the node, resulting in a denial of service. Preconditions include Exploitation requires policymaker privileges and roughly one million requests.. This issue is fixed in versions 4.2.7 and 4.3.1.