Answer in brief
CVE-2026-66077 records a High severity (CVSS 7.3) vulnerability in RabbitMQ: Stored XSS via TLS peer-certificate DN in management UI. The current sources do not mark it as known exploited. The current feed maps rabbitmq/rabbitmq-server (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 7.3. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps rabbitmq/rabbitmq-server (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| rabbitmq/rabbitmq-servergeneric | >=3.13.0 <3.13.15 || >=4.0.0 <4.0.20 || >=4.1.0 <4.1.11 || >=4.2.0 <4.2.6 | 3.13.15, 4.0.20, 4.1.11, 4.2.6 |
Published upstream
Sep 23, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Sep 23, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Sep 23, 2026
RabbitMQ is a messaging and streaming broker. Prior to versions 3.13.15, 4.0.20, 4.1.11, and 4.2.6, The management UI uses EJS 1.0 in which <%= ... %> does NOT HTML-escape. connection.ejs:135 renders <%= connection.ssl_details.peer_cert_subject %> (and peer_cert_issuer) directly into the page. The same pattern appears in streamConnection.ejs:102,106,110. The values come from rabbit_ssl:peer_cert_subject/1 which formats the DN as a string without HTML escaping. The verifier corrected the original researcher's claim: this is reachable only when the listener is configured with verify_peer (so the certificate must be signed by a CA in the broker's trust store, not arbitrary self-signed); however, in deployments using mTLS for client authentication, any user who can request a certificate from the organisational CA controls the Subject CN. An attacker who can obtain a TLS client certificate signed by a CA the broker trusts (with verify_peer enabled) can embed JavaScript in the certificate's Subject DN. When any administrator views that connection in the management UI, the script executes in the admin's browser session, allowing full account takeover (create users, export definitions, etc.). The management UI's CSP includes 'unsafe-inline', so inline script execution is not blocked. Preconditions include TLS listener configured with ssl_options.verify = verify_peer Attacker can obtain a CA-signed client certificate with attacker-chosen Subject (e.g. self-service corporate PKI, or rabbitmq_trust_store plugin in use) Administrator views the connection detail page. This issue is fixed in versions 3.13.15, 4.0.20, 4.1.11, and 4.2.6.
Quoted source text, attributed separately from HOL analysis.