Vulnerability · Published Sep 25, 2026 · Assigned by GitHub_M
CVE-2026-66071RabbitMQ: Atom exhaustion: OAuth2 JWT tag: scope values
Medium 6.0
In plain English
A medium-severity uncontrolled resource consumption in rabbitmq-server from rabbitmq. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 46% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
RabbitMQ is a messaging and streaming broker. From 3.13.0 until 3.13.15 and 4.0.22 and 4.1.11 and 4.2.6 and 4.3.1, Atom exhaustion: OAuth2 JWT tag: scope values. extractscopes/1 parses scopes of the form .tag: and calls rabbitdatacoercion:toatom() to convert to a tag atom. The token signature is verified first, so the attacker cannot forge scopes , but in IdP configurations where scope content is user-influenced, each login with a novel tag value leaks one In deployments where users can influence the scopes included in their IdP-issued JWT rabbitmqauthbackendoauth2 enabled IdP permits attacker-influenced scope values in signed tokens. This issue is fixed in versions 3.13.15 and 4.0.22 and 4.1.11 and 4.2.6 and 4.3.1.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | rabbitmq-server | no fix listed | DEBIAN-CVE-2026-66071 |
| Debian:13 | rabbitmq-server | no fix listed | DEBIAN-CVE-2026-66071 |
| Debian:14 | rabbitmq-server | 4.3.2-1 | DEBIAN-CVE-2026-66071 |
| Ubuntu:22.04:LTS | rabbitmq-server | no fix listed | UBUNTU-CVE-2026-66071 |
| Ubuntu:24.04:LTS | rabbitmq-server | no fix listed | UBUNTU-CVE-2026-66071 |
| Ubuntu:26.04:LTS | rabbitmq-server | no fix listed | UBUNTU-CVE-2026-66071 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| rabbitmq | rabbitmq-server | >= 3.13.0, < 3.13.15>= 4.0.0, < 4.0.22>= 4.1.0, < 4.1.11>= 4.2.0, < 4.2.6>= 4.3.0, < 4.3.1 |
Weakness: CWE-400 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
References
- https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-89p2-f5cv-x5cg x_refsource_CONFIRM
- https://github.com/rabbitmq/rabbitmq-server/commit/9a44124d9c932d6fc7d2a3b945e5a143e547bcb6 x_refsource_MISC
- https://github.com/rabbitmq/rabbitmq-server/commit/c5690583a53789a3bf00cca508b43e8246db0d11 x_refsource_MISC
- https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.2.6 x_refsource_MISC
- https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.3.1 x_refsource_MISC