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RabbitMQ amqp091-go: Connection Configuration Overwrite via Unsanitized TLS Path Parameter Injection

High severity GitHub Reviewed Published Jul 22, 2026 in rabbitmq/amqp091-go • Updated Sep 17, 2026

Package

gomod github.com/rabbitmq/amqp091-go (Go)

Affected versions

< 1.13.0

Patched versions

1.13.0

Description

Summary

A query parameter injection vulnerability exists in the AMQP client's connection URI formatting logic. When generating or parsing connection URIs, TLS-related filesystem paths (such as certificates or keys) are appended directly to the URI's query string using string concatenation rather than secure URL encoding via functions like url.QueryEscape.

If an application handles a TLS file path containing special character delimiters (such as & or =), these characters are interpreted as parameter separators by the URI parser. If the resulting URI.String() output is subsequently re-parsed via ParseURI, the injected fields can silently overwrite or hijack critical configuration parameters, forcing the client to use arbitrary connection settings or alternate TLS files.

Vulnerability Details

Mechanism

The vulnerability lies within the lack of proper escaping when compiling connection string components into a raw URL format:

// Example of insecure string concatenation during URI building
uri := fmt.Sprintf("amqps://user:pass@host/%s?certfile=%s&keyfile=%s", vhost, certPath, keyPath)

Because certPath and keyPath are not passed through url.QueryEscape, special URL characters preserve their control meanings. For instance, if a user supply a certificate path named:
/tmp/cert=foo&keyfile=/evil/path

The generated string translates into:
...?certfile=/tmp/cert=foo&keyfile=/evil/path&keyfile=/original/path

When this string passes back through ParseURI (common in connection re-dial routines or configuration replication steps), standard URL parsing mechanics treat the string as multiple distinct parameters. Depending on map assignment order inside the parser, the injected keys take precedence over the original parameters.

Impact

By manipulating the file paths used for TLS assets, an attacker or compromised local sub-system can:

  • Inject arbitrary alternative options or override protocol settings.
  • Substitute or switch keyfiles, leading to connection failures or the parsing of unauthorized cryptographic assets.
  • Corrupt connection state variables, triggering application-layer failures during connection setup or recovery.

Attack Vector

An attacker who has partial control over directory naming conventions or environmental variables used to specify local infrastructure paths can execute a parameter injection attack:

  1. Path Creation: An attacker sets up a path containing deliberate URL parameter delimiters (e.g., /var/lib/certs/client.crt?cacertfile=/tmp/fake_ca.crt&).
  2. String Generation: The application serializes the active connection state or passes the paths down to an unescaped URI builder function.
  3. Configuration Hijack: The URI string is generated with the injected parameter embedded into the query structure. When the client attempts to reuse or re-parse this connection string during a connection retry or worker spin-up, it parses the injected cacertfile parameter, loading a different, unverified Certificate Authority string.

References

@suchitd suchitd published to rabbitmq/amqp091-go Jul 22, 2026
Published by the National Vulnerability Database Sep 16, 2026
Published to the GitHub Advisory Database Sep 17, 2026
Reviewed Sep 17, 2026
Last updated Sep 17, 2026

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v4 base metrics

Exploitability Metrics
Attack Vector Local
Attack Complexity Low
Attack Requirements Present
Privileges Required Low
User interaction None
Vulnerable System Impact Metrics
Confidentiality High
Integrity High
Availability High
Subsequent System Impact Metrics
Confidentiality High
Integrity High
Availability Low

CVSS v4 base metrics

Exploitability Metrics
Attack Vector: This metric reflects the context by which vulnerability exploitation is possible. This metric value (and consequently the resulting severity) will be larger the more remote (logically, and physically) an attacker can be in order to exploit the vulnerable system. The assumption is that the number of potential attackers for a vulnerability that could be exploited from across a network is larger than the number of potential attackers that could exploit a vulnerability requiring physical access to a device, and therefore warrants a greater severity.
Attack Complexity: This metric captures measurable actions that must be taken by the attacker to actively evade or circumvent existing built-in security-enhancing conditions in order to obtain a working exploit. These are conditions whose primary purpose is to increase security and/or increase exploit engineering complexity. A vulnerability exploitable without a target-specific variable has a lower complexity than a vulnerability that would require non-trivial customization. This metric is meant to capture security mechanisms utilized by the vulnerable system.
Attack Requirements: This metric captures the prerequisite deployment and execution conditions or variables of the vulnerable system that enable the attack. These differ from security-enhancing techniques/technologies (ref Attack Complexity) as the primary purpose of these conditions is not to explicitly mitigate attacks, but rather, emerge naturally as a consequence of the deployment and execution of the vulnerable system.
Privileges Required: This metric describes the level of privileges an attacker must possess prior to successfully exploiting the vulnerability. The method by which the attacker obtains privileged credentials prior to the attack (e.g., free trial accounts), is outside the scope of this metric. Generally, self-service provisioned accounts do not constitute a privilege requirement if the attacker can grant themselves privileges as part of the attack.
User interaction: This metric captures the requirement for a human user, other than the attacker, to participate in the successful compromise of the vulnerable system. This metric determines whether the vulnerability can be exploited solely at the will of the attacker, or whether a separate user (or user-initiated process) must participate in some manner.
Vulnerable System Impact Metrics
Confidentiality: This metric measures the impact to the confidentiality of the information managed by the VULNERABLE SYSTEM due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.
Integrity: This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. Integrity of the VULNERABLE SYSTEM is impacted when an attacker makes unauthorized modification of system data. Integrity is also impacted when a system user can repudiate critical actions taken in the context of the system (e.g. due to insufficient logging).
Availability: This metric measures the impact to the availability of the VULNERABLE SYSTEM resulting from a successfully exploited vulnerability. While the Confidentiality and Integrity impact metrics apply to the loss of confidentiality or integrity of data (e.g., information, files) used by the system, this metric refers to the loss of availability of the impacted system itself, such as a networked service (e.g., web, database, email). Since availability refers to the accessibility of information resources, attacks that consume network bandwidth, processor cycles, or disk space all impact the availability of a system.
Subsequent System Impact Metrics
Confidentiality: This metric measures the impact to the confidentiality of the information managed by the SUBSEQUENT SYSTEM due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.
Integrity: This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. Integrity of the SUBSEQUENT SYSTEM is impacted when an attacker makes unauthorized modification of system data. Integrity is also impacted when a system user can repudiate critical actions taken in the context of the system (e.g. due to insufficient logging).
Availability: This metric measures the impact to the availability of the SUBSEQUENT SYSTEM resulting from a successfully exploited vulnerability. While the Confidentiality and Integrity impact metrics apply to the loss of confidentiality or integrity of data (e.g., information, files) used by the system, this metric refers to the loss of availability of the impacted system itself, such as a networked service (e.g., web, database, email). Since availability refers to the accessibility of information resources, attacks that consume network bandwidth, processor cycles, or disk space all impact the availability of a system.
CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:L

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(1st percentile)

Weaknesses

Improper Encoding or Escaping of Output

The product prepares a structured message for communication with another component, but encoding or escaping of the data is either missing or done incorrectly. As a result, the intended structure of the message is not preserved. Learn more on MITRE.

CVE ID

CVE-2026-77404

GHSA ID

GHSA-465g-fh3v-9jw4

Source code

Credits

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