RabbitMQ is a messaging and streaming broker. From 3.13.0 until 3.13.19, 4.0.24, 4.1.15, 4.2.10, and 4.3.5, RabbitMQ OAuth credential refresh retains revoked runtime tags. when an existing AMQP connection refreshes from an OAuth token that grants the impersonator tag to a valid same-username token that no longer grants that tag, RabbitMQ updates the OAuth backend implementation (token/scopes/expiry) but leaves the connection's runtime #user.tags unchanged. rabbitaccesscontrol:checkuserid/2 then still honors the stale impersonator tag, so the connection (including newly opened channels) can continue publishing messages with a foreign AMQP userid after that privilege should have been revoked. A fresh connection using the downgraded token correctly refuses the same publish, proving the defect is stale session state rather than the token Limited to connections that once held impersonator and successfully refresh to a downgraded same-username rabbitauthbackendoauth2 (or an equivalent refresh-capable backend that returns tags) is enabled for This issue is fixed in versions 3.13.19, 4.0.24, 4.1.15, 4.2.10, and 4.3.5.
CVE-2026-67420
This low-severity CVE scores 2.3 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.2% (13th percentile of EPSS-scored CVEs). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
- Lower severity and no public exploit yet
A fix is available — apply it.
- CVSS v3
- 2.3
- EG Score
- 2.3LOWmedium confidence
- EG Risk
- 26EG Risk 26/100CISA SSVC
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity23% × 45%Exploitation40% × 40%Automatability0% × 15%CISA SSVC: Track at low, Track* at medium and Attend at high mission impact.Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high. - EPSS PROB
- 0.2%
- EPSS %ILE
- 13th
- KEV
- Not listed
CISA SSVCTrack at low, Track* at medium and Attend at high mission impact.
A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table
Published
September 25, 2026
Last Modified
September 29, 2026
References (4)
- security-advisories@githubhttps://github.com/rabbitmq/rabbitmq-server/commit/5de287d213765ca592ff5848ad2f6b9b98ee6772
- security-advisories@githubhttps://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.3.5
- security-advisories@githubhttps://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-86fm-44m9-rqjx
- 134c704f-9b21-4f2e-91b3-4a467353bcc0https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-86fm-44m9-rqjx
Vendor Advisories for CVE-2026-67420(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Patch Availability(1)
| Vendor / Ecosystem | Fixed in / Patch | Released | Source |
|---|---|---|---|
| redhat | rabbitmq-server4-3-main-4.3.6-1.hum1 | 2026-09-15 | redhat |
Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 13× in last 7d / 18× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-10-03 14:26 UTCEPSS rescore
- 2026-10-02 22:26 UTCEG score recompute
- 2026-10-02 22:26 UTCVendor advisory
- 2026-10-02 17:56 UTCEPSS rescore
- 2026-10-01 19:50 UTCEPSS rescore
- 2026-09-30 15:03 UTCEPSS rescore
- 2026-09-29 20:31 UTCEG score recompute
- 2026-09-29 20:31 UTCVendor advisory
- 2026-09-29 19:44 UTCEG score recompute
- 2026-09-29 19:44 UTCVendor advisory
- 2026-09-28 14:44 UTCEG score recompute
- 2026-09-28 14:44 UTCVendor advisory
- 2026-09-28 13:52 UTCEPSS rescore
- 2026-09-27 13:48 UTCEPSS rescore
- 2026-09-26 15:59 UTCEPSS rescore
- 2026-09-25 17:33 UTCEG score recompute
- 2026-09-25 16:49 UTCEG score recompute
- 2026-09-25 16:49 UTCMITRE cvelistV5first tracked
Related CVEs(same vendor + same CWE)
Same vendor
10 shownredhat:RHSA-2026:67552
Frequently asked(5)
What is CVE-2026-67420?
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Dependency Blast Radius
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