CVE-2026-67231

Critical

Description

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.

SeverityCritical
CVSS9.1
Exploit probability—
ProductBroadcom Rabbitmq Server
PublishedSep 23, 2026
First seenSep 23, 2026
Weakness typeCWE-295CWE-295

How to fix

Update
  • broadcom rabbitmq_server3.13.15, 4.0.20, 4.1.11, 4.2.6 or later

Affected products

ProductAffected versionsFixed in
broadcom rabbitmq_server3.13.0 ≤ v < 3.13.15, 4.0.0 ≤ v < 4.0.20, 4.1.0 ≤ v < 4.1.11, 4.2.0 ≤ v < 4.2.63.13.15, 4.0.20, 4.1.11, 4.2.6

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CVE-2026-67231 · Broadcom Rabbitmq Server · Dark Radar