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Vulnerabilities

Vulnerability · CVE-2026-66077

RabbitMQ: Stored XSS via TLS peer-certificate DN in management UI

Published Sep 23, 2026 · catalog updated Sep 29, 2026 · RabbitMQ: Stored XSS via

Check if you run it

No confirmed exploitation is on record for CVE-2026-66077. EPSS is 0.30%. Act only if a listed version of RabbitMQ: Stored XSS via is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (RabbitMQ: Stored XSS via).
  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
High7.3
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.30%
Remediation
Advisory link
Affected products
vendor rabbitmq rabbitmq-server

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 (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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • vendor rabbitmq rabbitmq-serverversion unspecified

How to fix CVE-2026-66077

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-66077. EPSS is 0.30%. Act only if a listed version of RabbitMQ: Stored XSS via is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-79: Cross-site Scripting (XSS). EPSS 0.30%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

Ubuntu security

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Sep 29, 2026 · CVE.org

    Updated

    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 (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 esca

  2. Oct 15, 2026 · Ubuntu Security Notices

    Detected

    CVE-2026-66077 is listed by USN-8933-1: RabbitMQ Server vulnerabilities.

Sources

  • CVE.orgVulnerability recordCVE-2026-66077

    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 (and peer_cert_issuer) directly into the page. The same pattern appears in streamConnection

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-66077

    30-day exploitation probability 0.3%

    first.org
  • Ubuntu Security NoticesVendor advisoryCVE-2026-66077

    It was discovered that RabbitMQ Server incorrectly handled CORS wildcard origin configuration. An attacker could possibly use this issue to cause a cross-site request forgery attack. This issue only affected Ubuntu 18.04 LTS, Ubuntu 20.04 LTS, Ubuntu 22.04 LTS, Ubuntu 24.04 LTS,

    ubuntu.com

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.