CVE-2026-67404: CWE-295: Improper Certificate Validation in rabbitmq rabbitmq-server
CVE-2026-67404 is a critical vulnerability in rabbitmq-server related to improper certificate validation. Prior to fixed versions, when no CA bundle is available, the SSL options fall back to no verification without warning. This allows a man-in-the-middle attacker to forge JWKS responses and cause the broker to accept arbitrary JWTs. The vulnerability requires the OAuth2 plugin to be in use without a configured cacertfile and an empty or unreadable OS CA bundle, such as in minimal container environments. The issue is fixed in versions 3.13.15, 4.0.20, 4.1.11, 4.2.6, and 4.3.0.
AI Analysis
Technical Summary
RabbitMQ server versions prior to 3.13.15, 4.0.20, 4.1.11, 4.2.6, and 4.3.0 improperly validate certificates when no CA bundle is available. In this case, ssl_options/1 falls back to [{verify, verify_none}] silently, allowing an attacker in a man-in-the-middle position to forge JWKS responses. This leads the broker to accept arbitrary JWTs, compromising authentication. Preconditions include use of the OAuth2 plugin without a cacertfile configured and an empty or unreadable OS CA bundle, such as in minimal container setups. The vulnerability is tracked as CWE-295 (Improper Certificate Validation) and has a CVSS 4.0 score of 9.2 (critical).
Potential Impact
An attacker positioned as a network man-in-the-middle can forge JWKS responses, causing the RabbitMQ broker to accept arbitrary JSON Web Tokens (JWTs). This undermines authentication and authorization controls, potentially allowing unauthorized access or actions within the messaging system. The impact is critical due to the high CVSS score and the ability to bypass security checks under specific conditions.
Mitigation Recommendations
This vulnerability is fixed in rabbitmq-server versions 3.13.15, 4.0.20, 4.1.11, 4.2.6, and 4.3.0. Users should upgrade to one of these versions or later to remediate the issue. Ensure that a proper CA bundle is configured and accessible, especially when using the OAuth2 plugin. Without upgrading, avoid running RabbitMQ in environments where the OS CA bundle is empty or unreadable and the OAuth2 plugin is enabled without a cacertfile.
CVE-2026-67404: CWE-295: Improper Certificate Validation in rabbitmq rabbitmq-server
Description
CVE-2026-67404 is a critical vulnerability in rabbitmq-server related to improper certificate validation. Prior to fixed versions, when no CA bundle is available, the SSL options fall back to no verification without warning. This allows a man-in-the-middle attacker to forge JWKS responses and cause the broker to accept arbitrary JWTs. The vulnerability requires the OAuth2 plugin to be in use without a configured cacertfile and an empty or unreadable OS CA bundle, such as in minimal container environments. The issue is fixed in versions 3.13.15, 4.0.20, 4.1.11, 4.2.6, and 4.3.0.
CVSS v4.0
Score 9.2critical
Affected software
rabbitmq
rabbitmq-server
pkg:github/rabbitmq/rabbitmq-serverRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
RabbitMQ server versions prior to 3.13.15, 4.0.20, 4.1.11, 4.2.6, and 4.3.0 improperly validate certificates when no CA bundle is available. In this case, ssl_options/1 falls back to [{verify, verify_none}] silently, allowing an attacker in a man-in-the-middle position to forge JWKS responses. This leads the broker to accept arbitrary JWTs, compromising authentication. Preconditions include use of the OAuth2 plugin without a cacertfile configured and an empty or unreadable OS CA bundle, such as in minimal container setups. The vulnerability is tracked as CWE-295 (Improper Certificate Validation) and has a CVSS 4.0 score of 9.2 (critical).
Potential Impact
An attacker positioned as a network man-in-the-middle can forge JWKS responses, causing the RabbitMQ broker to accept arbitrary JSON Web Tokens (JWTs). This undermines authentication and authorization controls, potentially allowing unauthorized access or actions within the messaging system. The impact is critical due to the high CVSS score and the ability to bypass security checks under specific conditions.
Mitigation Recommendations
This vulnerability is fixed in rabbitmq-server versions 3.13.15, 4.0.20, 4.1.11, 4.2.6, and 4.3.0. Users should upgrade to one of these versions or later to remediate the issue. Ensure that a proper CA bundle is configured and accessible, especially when using the OAuth2 plugin. Without upgrading, avoid running RabbitMQ in environments where the OS CA bundle is empty or unreadable and the OAuth2 plugin is enabled without a cacertfile.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-07-29T15:02:20.411Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6ab43799f7a7c541064a965a
Added to database: 09/23/2026, 20:33:29 UTC
Last enriched: 09/23/2026, 20:47:42 UTC
Last updated: 09/23/2026, 23:25:07 UTC
Views: 7
Community Reviews
0 reviewsCrowdsource mitigation strategies, share intel context, and vote on the most helpful responses. Sign in to add your voice and help keep defenders ahead.
Want to contribute mitigation steps or threat intel context? Sign in or create an account to join the community discussion.
Actions
Updates to AI analysis require Pro Console access. Upgrade inside Console → Billing.
Need more coverage?
Upgrade to Pro Console for AI refresh and higher limits.
For incident response and remediation, OffSeq services can help resolve threats faster.
Latest Threats
Check if your credentials are on the dark web
Instant breach scanning across billions of leaked records. Free tier available.