Vulnerability Details CVE-2026-67231
RabbitMQ is a messaging and streaming broker. Prior to versions 3.13.15, 4.0.20, 4.1.11, 4.2.6, and 4.3.0, The trust-store plugin installs a verify_fun that overrides {bad_cert, unknown_ca} / {bad_cert, selfsigned_peer} when the presented cert "matches" a whitelisted one. The match key is extract_issuer_id/1 → public_key:pkix_issuer_id/2 → {IssuerName, SerialNumber} , both fields are taken verbatim from the presented certificate body and contain no public-key, SKI, fingerprint or signature material. is_whitelisted/1 is a pure ets:member lookup; the stored full DER is used only for list/0 display and is never compared against the presented cert. cacerts is [], so the whitelisted cert is never used as a trust anchor for path validation either. TLS client-authentication bypass: an attacker who knows the issuer DN + serial of any whitelisted certificate can connect with a forged self-signed cert. Preconditions include rabbitmq_trust_store plugin enabled and used as the TLS verify_fun Attacker knows or can guess the {Issuer, Serial} of at least one whitelisted cert (non-secret; exposed via CLI/logs/any cert copy). This issue is fixed in versions 3.13.15, 4.0.20, 4.1.11, 4.2.6, and 4.3.0.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.002
EPSS Ranking 15.2%
CVSS Severity
CVSS v3 Score 9.1
Products affected by CVE-2026-67231
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cpe:2.3:a:broadcom:rabbitmq_server:4.0.0
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cpe:2.3:a:broadcom:rabbitmq_server:4.0.1
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cpe:2.3:a:broadcom:rabbitmq_server:4.0.10
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cpe:2.3:a:broadcom:rabbitmq_server:4.0.11
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cpe:2.3:a:broadcom:rabbitmq_server:4.0.12
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cpe:2.3:a:broadcom:rabbitmq_server:4.0.13
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cpe:2.3:a:broadcom:rabbitmq_server:4.0.14
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cpe:2.3:a:broadcom:rabbitmq_server:4.0.15
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cpe:2.3:a:broadcom:rabbitmq_server:4.0.16
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cpe:2.3:a:broadcom:rabbitmq_server:4.0.17
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cpe:2.3:a:broadcom:rabbitmq_server:4.0.18
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cpe:2.3:a:broadcom:rabbitmq_server:4.0.19
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cpe:2.3:a:broadcom:rabbitmq_server:4.0.2
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cpe:2.3:a:broadcom:rabbitmq_server:4.0.3
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cpe:2.3:a:broadcom:rabbitmq_server:4.0.4
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cpe:2.3:a:broadcom:rabbitmq_server:4.0.5
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cpe:2.3:a:broadcom:rabbitmq_server:4.0.6
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cpe:2.3:a:broadcom:rabbitmq_server:4.0.7
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cpe:2.3:a:broadcom:rabbitmq_server:4.0.8
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cpe:2.3:a:broadcom:rabbitmq_server:4.0.9
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cpe:2.3:a:broadcom:rabbitmq_server:4.2.0
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cpe:2.3:a:broadcom:rabbitmq_server:4.2.1
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cpe:2.3:a:broadcom:rabbitmq_server:4.2.2
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cpe:2.3:a:broadcom:rabbitmq_server:4.2.3
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cpe:2.3:a:broadcom:rabbitmq_server:4.2.4
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cpe:2.3:a:broadcom:rabbitmq_server:4.2.5