RabbitMQ: Federation upstream skips vhost authorization allowing cross-vhost message access
RabbitMQ is a messaging and streaming broker. From 3.13.0 until 4.3.3, 4.2.9 , 4.1.14, 4.0.24, and 3.13.18, Federation upstream in RabbitMQ skips vhost authorization allowing cross-vhost message access. what the bug lets you do. A policymaker on one vhost reads and drains messages out of another vhost it has no permission on. With the default ack-mode the source messages are consumed (deleted), not copied. Why that should not 1. Federation validates the upstream URI without any vhost-access Cross-vhost message read/drain from a per-vhost policymaker, breaking vhost tenancy This issue is fixed in versions 4.3.3, 4.2.9 , 4.1.14, 4.0.24, and 3.13.18.
- Published
- Sep 25, 2026
- Updated
- Sep 28, 2026
- EPSS
- 0.3% · 21th percentile
- CWE
- CWE-862
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Report tools
Action score
24
Monitor
Low priority for now.
- CVSS
- 24 / 40 · 6.0 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.3%
CISA SSVC decision
- Exploitation
- proof of concept
- Automatable
- no
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · GitHub_M
- 6.0
- NVD has not scored this yet; the score shown is the CNA’s.
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:L/SI:N/SA:N
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Affected systems
—
Versions reported by the vendor
Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.
rabbitmq rabbitmq-server
- >= 4.3.0, < 4.3.3, >= 4.2.0, < 4.2.9, >= 4.1.0, < 4.1.14, >= 4.0.0, < 4.0.24, >= 3.13.0, < 3.13.18affected
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:12 | rabbitmq-server | all versions | — |
Same product
rabbitmq: all recordsOther highest-scoring records for the same primary product.
- CVE-2026-67404RabbitMQ: OAuth2 silent verify_none fallback for JWKS fetch36Monitor
- CVE-2026-67231RabbitMQ: Trust-store whitelist by Issuer+Serial only36Monitor
- CVE-2026-67410RabbitMQ: OAuth2 Client Secret Exposed via Unauthenticated JavaScript Endpoint32Monitor
- CVE-2026-67409RabbitMQ: JWKS Fetch Ignores HTTP Response Status Code - Signing Key Destruction Causes Authentication DoS32Monitor
- CVE-2026-67236RabbitMQ: Plaintext username:password stored in an insecure cookie after successful POST /login32Monitor
- CVE-2026-66079RabbitMQ: Pre-auth AMQP 1.0 array32 zero-width element DoS32Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
No fix version is recorded for this entry. Check the references for vendor advisories.
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
- CVE-2026-672331 days apartRabbitMQ: Monitoring-tag user can DELETE shovels24Monitor
- CVE-2026-674070 days apartRabbitMQ: Incomplete fix for CVE-2026-44838: `escape_regex_char/1` does not escape `-`, leaving room for an MQTT topic permission bypass20Monitor
- CVE-2026-672410 days apartRabbitMQ: AMQP 1.0 management exchange.declare skips alternate-exchange permission check19Monitor
- CVE-2026-674210 days apartRabbitMQ: Stored HTML Injection in RabbitMQ Management OAuth Error Handling18Monitor
- CVE-2026-674200 days apartRabbitMQ OAuth credential refresh retains revoked runtime tags9Monitor
- CVE-2026-660752 days apartRabbitMQ: Monitoring-tag user can restart federation links9Monitor
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- A low-privileged account is enough.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- Integrity
- Availability
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- X
Weakness class (CWE)
CWE-862 · Missing AuthorizationCVSS vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:L/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
nvd-secondary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.
References
- github.com/rabbitmq/rabbitmq-server/releases/tag/v4.2.9
- github.com/rabbitmq/rabbitmq-server/releases/tag/v4.3.3
- github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-42pc-678q-v8qj
Vendor advisories and official records. Exploit/PoC links are deliberately left out.