RabbitMQ prior 3.13.15/4.0.20/4.1.11/4.2.6 Bulk Delete /api/users/bulk-delete rabbitauthbackendinternal:deleteuser access control

Summaryinfo

A vulnerability categorized as problematic has been discovered in RabbitMQ prior 3.13.15/4.0.20/4.1.11/4.2.6. This issue affects the function rabbitauthbackendinternal:deleteuser of the file /api/users/bulk-delete of the component Bulk Delete. Such manipulation leads to access control. This vulnerability is listed as CVE-2026-66078. The attack may be performed from remote. There is no available exploit.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in RabbitMQ prior 3.13.15/4.0.20/4.1.11/4.2.6. Affected by this issue is the function rabbitauthbackendinternal:deleteuser of the file /api/users/bulk-delete of the component Bulk Delete. The manipulation with an unknown input leads to a access control vulnerability. Using CWE to declare the problem leads to CWE-284. The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor. Impacted is integrity, and availability. CVE summarizes:

RabbitMQ is a messaging and streaming broker. From 3.13.0 until 3.13.15 and 4.0.20 and 4.1.11 and 4.2.6, protected tag bypass via bulk-delete. dELETE /api/users/:name refuses to delete users tagged protected (rabbitmgmtwmuser:deleteresource/2 checks isprotecteduser). POST /api/users/bulk-delete iterates the supplied username list and calls rabbitauthbackendinternal:deleteuser/2 directly , that function has no protected-tag check , so the guard is silently An administrator can delete protected-tagged service accounts via the bulk endpoint, bypassing a safeguard the test suite confirms is rabbitmqmanagement enabled Attacker has the administrator tag A protected-tagged user. This issue is fixed in versions 3.13.15 and 4.0.20 and 4.1.11 and 4.2.6.

The advisory is shared for download at github.com. This vulnerability is handled as CVE-2026-66078 since 07/24/2026. The exploitation is known to be easy. The attack may be launched remotely. Additional levels of successful authentication are necessary for exploitation. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 09/25/2026). The MITRE ATT&CK project declares the attack technique as T1068.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Name

• RabbitMQ

Version

• 4.0.20
• 4.1.11
• 4.2.6
• <3.13.15

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