All vulnerabilities
CVE-2026-66071GHSA-89p2-f5cv-x5cg

rabbitmq-server: RabbitMQ: Atom exhaustion: OAuth2 JWT tag: scope values

rabbitmq rabbitmq-server
Open in ThreatlineRecord JSON
CVSS
6.0Medium
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.47%Chance of exploitation activity in the next 30 days, higher than 40% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed inNone listedNo source names a fixed version. Check the vendor advisory below
Published25 Sep 2026Updated 25 Sep 2026CVE List

What fixes it

No source in this snapshot names a fixed version. The vendor advisories under References are the place to check.

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.

Text from CVE List

Affected versions 5

  • rabbitmq-serveraffected: >= 3.13.0, < 3.13.15CVE List
  • rabbitmq-serveraffected: >= 4.0.0, < 4.0.22CVE List
  • rabbitmq-serveraffected: >= 4.1.0, < 4.1.11CVE List
  • rabbitmq-serveraffected: >= 4.2.0, < 4.2.6CVE List
  • rabbitmq-serveraffected: >= 4.3.0, < 4.3.1CVE List

References 5