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Vulnerability · Published Sep 23, 2026 · Assigned by GitHub_M

CVE-2026-67231RabbitMQ: Trust-store whitelist by Issuer+Serial only

Critical 9.1

In plain English

A critical-severity improper certificate validation in rabbitmq-server from rabbitmq. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 14% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)9.1Critical
Exploit odds (30 days)0.2%top 86.4% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12rabbitmq-serverno fix listedDEBIAN-CVE-2026-67231
Debian:13rabbitmq-serverno fix listedDEBIAN-CVE-2026-67231
Debian:14rabbitmq-server4.3.0-2DEBIAN-CVE-2026-67231
Ubuntu:22.04:LTSrabbitmq-server3.9.27-0ubuntu0.6UBUNTU-CVE-2026-67231
Ubuntu:22.04:LTSrabbitmq-server3.9.27-0ubuntu0.6USN-8933-1
Ubuntu:24.04:LTSrabbitmq-server3.12.1-1ubuntu1.7USN-8933-1
Ubuntu:24.04:LTSrabbitmq-server3.12.1-1ubuntu1.7UBUNTU-CVE-2026-67231
Ubuntu:26.04:LTSrabbitmq-server4.0.5-10ubuntu5.2USN-8933-1
Ubuntu:26.04:LTSrabbitmq-server4.0.5-10ubuntu5.2UBUNTU-CVE-2026-67231

Affected products (as reported)

VendorProductVersions
rabbitmq rabbitmq-server >= 3.13.0, < 3.13.15>= 4.0.0, < 4.0.20>= 4.1.0, < 4.1.11>= 4.2.0, < 4.2.6

Weakness: CWE-295 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

References