CVE-2026-67419

RabbitMQ: Consecutive topic wildcards cause combinatorial routing work

MEDIUM
6.5
CVSS Score
Published: September 25, 2026 at 04:41 PM UTC
Updated: October 16, 2026 at 03:46 PM UTC
2 products affected across 2 vendorsRabbitmq ServerRabbitmq Server

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Severity
MEDIUM6.5
Exploit prediction
EPSS 0.4%
SSVC
PoC

Description

RabbitMQ is a messaging and streaming broker. Prior to 4.3.5, an authenticated user who can bind a queue to a topic exchange and publish to it can use consecutive # segments in a binding key to make both topic matchers revisit the same trie-node and routing-key-suffix states without memoization. The matcher materializes duplicate destinations before deduplication, causing combinatorial CPU work and memory pressure that can disrupt routing for all tenants. This vulnerability is fixed in 4.3.5.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

4.3.0 ≤ v < 4.3.5
v < 4.3.5
Affected range stops below 4.3.5, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (3)

SSVC — Action Prioritization

SSVCPoCNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-407CWE-1333

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