CVE-2026-66077Public exploitNetwork attack vectorHinoki check available

Administrator account takeover via unescaped certificate DN

Published Sep 23, 2026 · Updated Sep 23, 2026

Stored XSS in the management UI of RabbitMQ Server allows remote authenticated users to seize administrator sessions through a client certificate. EJS templates render peer certificate subject and issuer strings from rabbit_ssl:peer_cert_subject/1 into connection pages without HTML escaping. Exploitation requires verify_peer, a trusted CA-signed certificate with an attacker-chosen subject, and an administrator to view the connection; the script then runs with that administrator session.

CVSS severity7.3
High
EPSS probability0.30%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Stored XSS in the management UI of RabbitMQ Server allows remote authenticated users to seize administrator sessions through a client certificate. EJS templates render peer certificate subject and issuer strings from rabbit_ssl:peer_cert_subject/1 into connection pages without HTML escaping. Exploitation requires verify_peer, a trusted CA-signed certificate with an attacker-chosen subject, and an administrator to view the connection; the script then runs with that administrator session.

The record

CVE
CVE-2026-66077
Published
Sep 23, 2026
Updated
Sep 23, 2026
Vendor
RabbitMQ
Product
RabbitMQ Server
Classifications
CWE-79, T1203
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 23, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 23, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 3.13.0, < 3.13.15
  2. Affected versionversion=>= 4.0.0, < 4.0.20
  3. Affected versionversion=>= 4.1.0, < 4.1.11
  4. Affected versionversion=>= 4.2.0, < 4.2.6

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

RabbitMQ · RabbitMQ Serverversion=>= 3.13.0, < 3.13.15; version=>= 4.0.0, < 4.0.20; version=>= 4.1.0, < 4.1.11; version=>= 4.2.0, < 4.2.6

Published CVSS scores

7.3RabbitMQCVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:A/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1203Exploitation for Client Execution

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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