Reference page — cumulative record through Monday, October 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.

CVE-2026-66071

CVE-2026-66071MEDIUM

RabbitMQ: Atom exhaustion: OAuth2 JWT tag: scope values

  AV  AC  AT  PR  UI  VC  VI  VA   CVSS    EPSS   %ile   KEV
   N   L   P   L   N   N   N   H    6.0   .0047   39.6     —

AFFECTED
  Product          Versions                Fixed
  rabbitmq-server  >= 3.13.0, < 3.13.15 –  —

TIMELINE
  Jul 23  Reserved by GitHub_M
  Sep 25  Published (CNA: GitHub_M)
  Oct 15  EXPLOIT PUBLISHED — CVE-2026-66071 (rabbitmq-server). Public exploit reference added.

CWE-400 · CNA: GitHub_M · CVSS v4.0 · 5 references · NVD status: Analyzed

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.

Lifecycle

Complete event history — 3 events, chronological
Date	Event	Detail
July 23, 2026	Reserved	Reserved by GitHub_M
September 25, 2026	Published	Published (CNA: GitHub_M)
October 15, 2026	EXPLOIT PUBLISHED	EXPLOIT PUBLISHED — CVE-2026-66071 (rabbitmq-server). Public exploit reference added.

Affected

Affected products and packages — 1 row
Vendor	Product / Package	Ecosystem	Version introduced	Fixed
rabbitmq	rabbitmq-server	—	>= 3.13.0, < 3.13.15	—

Weaknesses

CWE-400

References (5)

https://github.com/rabbitmq/rabbitmq-server/commit/9a44124d9c932d6fc7d2a3b945e5a143e547bcb6 [Patch]
https://github.com/rabbitmq/rabbitmq-server/commit/c5690583a53789a3bf00cca508b43e8246db0d11 [Patch]
https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.2.6 [Release Notes]
https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.3.1 [Release Notes]
https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-89p2-f5cv-x5cg [Exploit, Third Party Advisory]

Authoritative record: CVE-2026-66071 at cve.org

Vendors: rabbitmq

Weaknesses: CWE-400

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-66071 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Monday, October 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.