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Kargo has Missing Authorization Vulnerabilities in Approval & Promotion REST API Endpoints

Moderate severity GitHub Reviewed Published Feb 17, 2026 in akuity/kargo • Updated Feb 23, 2026

Package

gomod github.com/akuity/kargo (Go)

Affected versions

>= 1.9.0, < 1.9.3

Patched versions

1.9.3

Description

Summary

Kargo's authorization model includes a promote verb -- a non-standard Kubernetes "dolphin verb" -- that gates the ability to advance Freight through a promotion pipeline. This verb exists to separate the ability to manage promotion-related resources from the ability to trigger promotions, enabling fine-grained access control over what is often a sensitive operation.

The promote verb is correctly enforced in Kargo's legacy gRPC API. However, three endpoints in the newer REST API omit this check, relying only on standard Kubernetes RBAC for the underlying resource operations (patch on freights/status or create on promotions). This permits users who hold those standard permissions -- but who were deliberately not granted promote -- to bypass the intended authorization boundary.

The affected endpoints are:

  1. POST /v1beta1/projects/{project}/freight/{freight}/approve

    Approves Freight for promotion to a specific Stage.

    The endpoint is intended to require both patch permission on Freight status and promote permission on the target Stage, but asserts only the former.

  2. POST /v1beta1/projects/{project}/stages/{stage}/promotions

    Promotes Freight to a specific Stage.

    The endpoint is intended to require both create permission on Promotion resources and promote permission on the target Stage, but asserts only the former.

  3. POST /v1beta1/projects/{project}/stages/{stage}/promotions/downstream

    Promotes Freight to all Stages immediately downstream of a given Stage.

    The endpoint is intended to require both create permission on Promotion resources and promote permission on each downstream Stage, but asserts only the former.

Base Metrics

The following sections provide the rationale for the values selected for each of CVSS v4's base metrics.

Attack Vector (AV): Network

The affected endpoints are part of Kargo's newer REST API, which is served over HTTP/HTTPS. (The analogous endpoints of the legacy gRPC API correctly check promote permission and are not affected.) No local or physical access is required.

Attack Complexity (AC): Low

The attack requires only well-formed API requests to the affected endpoints.

Attack Requirements (AT): None

No specific environmental conditions are required beyond those that are typical for any Kargo instance.

Privileges Required (PR): Low

The attacker must hold permissions to patch Freight status and/or create Promotion resources. These are standard operational permissions commonly granted to some Kargo users and do not represent what CVSS formally considers administrative or elevated access.

User Interaction (UI): None

The attack is fully automated via API calls. No other user needs to take any action.

Confidentiality Impact to Vulnerable System (VC): None

The vulnerability does not expose any data from the Kargo control plane.

Integrity Impact to Vulnerable System (VI): Low

The attacker can coerce a Stage into a state it might not otherwise transition to. This constitutes bounded state corruption within a single Project. Kargo itself continues to function correctly.

Availability Impact to Vulnerable System (VA): None

Promotion resources created by exploitation of this vulnerability consume the same controller resources as a legitimate Promotion would. A user with proper promote permissions could generate identical load. The vulnerability does not introduce any new avenue for resource exhaustion.

Confidentiality Impact to Subsequent Systems (SC): None

The vulnerability does not provide any mechanism for the attacker to read data from downstream systems.

Integrity Impact to Subsequent Systems (SI): Low

Critically, the attacker does not control the content of Freight resources without artifact repositories also having been compromised. In isolation, which is how vulnerabilities are scored, the worst consequence of a successful attack is downstream systems (e.g. Argo CD) deploying incorrect revisions of artifacts, which in some cases should have been rejected by bypassed segments of the promotion pipeline. Though the operational consequences land on subsequent systems, they are bounded by the attacker's inability to inject arbitrary content.

Availability Impact to Subsequent Systems (SA): None

The attack does not provide any mechanism to degrade the availability of downstream systems beyond what could be achieved with legitimately promoted Freight.

Mitigating Factors

  • Only the REST API endpoints introduced in v1.9.0 are affected. The legacy gRPC API and the Kargo UI (which uses the gRPC API) correctly enforce the promote permission check and are not vulnerable.

  • The window of affected versions is narrow: v1.9.0 through v1.9.2.

  • Exploitation requires authentication to the Kargo API server and specific operational permissions (patch on freights/status or create on promotions). Anonymous or minimally privileged users cannot exploit this vulnerability.

  • Impact is bounded to a single Project. The promote bypass does not enable cross-Project access or escalation beyond the namespace in which the attacker already holds the prerequisite permissions.

  • There is no evidence of exploitation in the wild.

References

@krancour krancour published to akuity/kargo Feb 17, 2026
Published to the GitHub Advisory Database Feb 19, 2026
Reviewed Feb 19, 2026
Published by the National Vulnerability Database Feb 20, 2026
Last updated Feb 23, 2026

Severity

Moderate

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 Network
Attack Complexity Low
Attack Requirements None
Privileges Required Low
User interaction None
Vulnerable System Impact Metrics
Confidentiality None
Integrity Low
Availability None
Subsequent System Impact Metrics
Confidentiality None
Integrity Low
Availability None

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:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N

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.
(9th percentile)

Weaknesses

Missing Authorization

The product does not perform an authorization check when an actor attempts to access a resource or perform an action. Learn more on MITRE.

CVE ID

CVE-2026-27111

GHSA ID

GHSA-5vvm-67pj-72g4

Source code

Credits

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