Vulnerability · Published Sep 25, 2026 · Assigned by GitHub_M
CVE-2026-67226RabbitMQ: Admin-only atom exhaustion: PUT /api/users tags list
Medium 6.9
In plain English
A medium-severity uncontrolled resource consumption in rabbitmq-server from rabbitmq. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 33% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | rabbitmq-server | no fix listed | DEBIAN-CVE-2026-67226 |
| Debian:13 | rabbitmq-server | no fix listed | DEBIAN-CVE-2026-67226 |
| Debian:14 | rabbitmq-server | 4.3.0-2 | DEBIAN-CVE-2026-67226 |
| Ubuntu:22.04:LTS | rabbitmq-server | no fix listed | UBUNTU-CVE-2026-67226 |
| Ubuntu:24.04:LTS | rabbitmq-server | no fix listed | UBUNTU-CVE-2026-67226 |
| Ubuntu:26.04:LTS | rabbitmq-server | no fix listed | UBUNTU-CVE-2026-67226 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| rabbitmq | rabbitmq-server | >= 4.0.0, < 4.0.22>= 4.1.0, < 4.1.14>= 4.2.0, < 4.2.7 |
Weakness: CWE-400 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N