CVE-2026-67226 RabbitMQ: Admin-only atom exhaustion: PUT /api/users tags list
An administrator can crash the RabbitMQ node by submitting a user creation request with an excessive number of tags, causing resource exhaustion.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-67226?
CVE-2026-67226 is a medium-severity denial of service vulnerability in Broadcom Rabbitmq Server, published on 25 Sep 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Official description
RabbitMQ is a messaging and streaming broker. From 4.0.0 until 4.0.22 and 4.1.14 and 4.2.7, Admin-only atom exhaustion: PUT /api/users tags list. settags/2 maps rabbitdatacoercion:toatom/1 over the user's tags list. The 20 MB management body limit fits ~3-4M short tag strings. An administrator can crash the node in a single request by creating a user (or importing definitions) with ~1M unique tag administrator. This issue is fixed in versions 4.0.22 and 4.1.14 and 4.2.7.
Weakness: CWE-400
Which versions are affected by CVE-2026-67226?
1 open source package ship an affected version, including rabbitmq. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
rabbitmq Bitnami | From 4.0.0 | 4.0.22, 4.1.14, 4.2.7 |
Products include Broadcom Rabbitmq Server.
How do I fix CVE-2026-67226?
Upgrade rabbitmq to a fixed version for your release line: 4.0.22, 4.1.14 or 4.2.7.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-67226 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-67226 exists.
Other vulnerabilities in Broadcom Rabbitmq Server
- CVE-2016-9877 Auth bypass in Pivotal RabbitMQ 3.x before 3.5.8 and 3.6.x before 3.6.6; RabbitMQ for PCF 1.5.x before 1.5.20, 1.6.x before 1.6.12 and 1.7.x before 1.7.7
- CVE-2026-67404 RabbitMQ: OAuth2 silent verify_none fallback for JWKS fetch
- CVE-2026-67231 RabbitMQ: Trust-store whitelist by Issuer+Serial only
- CVE-2026-57219 Information disclosure in rabbitmq-server
- CVE-2026-67236 RabbitMQ: Plaintext username:password stored in an insecure cookie after successful POST /login
Sources
Also known as AZL-105765, BIT-rabbitmq-2026-67226, DEBIAN-CVE-2026-67226, GHSA-34c7-r8w9-5wv8, UBUNTU-CVE-2026-67226.