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Path/URL injection into generated Copilot plugin manifest via x-ai-* extensions (Microsoft Kiota)

Critical
jingjingjia-ms published GHSA-4jwf-m4wg-8p66 Jul 3, 2026

Package

nuget Microsoft.OpenApi.Kiota (NuGet)

Affected versions

>= 1.30.0, < 1.32.5
< 1.29.1

Patched versions

1.32.5
1.29.1
nuget Microsoft.OpenApi.Kiota.Builder (NuGet)
>= 1.30.0, < 1.32.5
< 1.29.1
1.32.5
1.29.1

Description

Summary

kiota plugin add / kiota plugin generate (with -t APIPlugin) emits an attacker-controlled static_template.file path from the AI-plugin extensions (x-ai-adaptive-card, x-ai-capabilities) verbatim, with no path validation, into the generated Microsoft 365 Copilot / Teams plugin manifest (<name>-apiplugin.json). An attacker-controlled or compromised OpenAPI description can therefore embed a ../ / absolute path into the manifest's response_semantics.static_template.file, yielding a path traversal (CWE-22) / out-of-package file inclusion (CWE-829) that is resolved by the AI host when the generated plugin is deployed.

Confirmed on Kiota 1.32.4 (KIOTA_CONFIG_PREVIEW=true, the self-contained linux-x64 release binary).

Details

Both extension paths write the static_template.file reference straight into the manifest without sanitization — PluginsGenerationService.GetResponseSemanticsFromAdaptiveCardExtension mints static_template = {"file": <File>}, and the x-ai-capabilities path copies the static_template object through:

# spec                                                  -> generated manifest (functions[].capabilities.response_semantics)
x-ai-adaptive-card: {title: T, data_path: $.x,
   file: "../../../../../../etc/passwd"}                -> static_template.file = "../../../../../../etc/passwd"   (CWE-22)
x-ai-capabilities.response_semantics.static_template:
   {file: "../../../../../../etc/passwd"}               -> static_template.file = "../../../../../../etc/passwd"   (CWE-22)

(x-ai-adaptive-card.file only reaches the manifest when title is set, so GetResponseSemanticsFromAdaptiveCardExtension fires; otherwise kiota writes its own template card instead.)

Impact

This is not local code execution on the build host. The injected path is written into the generated plugin manifest and realized downstream, when the plugin is packaged and sideloaded / deployed to an AI host (Microsoft 365 Copilot / Teams) that resolves static_template.file relative to the plugin package (out-of-package file reference via ../). Kiota is the propagation point: it fails to reject ../ and absolute paths in this provider-supplied field before writing it into the manifest.

Patches

Fixed in 1.32.5 (#7892). static_template.file from both x-ai-adaptive-card and x-ai-capabilities is validated as a relative path confined to the plugin output package: absolute URIs, rooted/UNC paths, Windows drive paths, and .. traversal segments are rejected, and unsafe references are dropped with a warning. Regression tests cover .., absolute paths, and URI values.

Remediation

Upgrade to Kiota 1.32.5 or later and regenerate affected plugins.

Severity

Critical

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 None
User interaction None
Vulnerable System Impact Metrics
Confidentiality High
Integrity High
Availability High
Subsequent System Impact Metrics
Confidentiality None
Integrity None
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:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

CVE ID

CVE-2026-59864

Weaknesses

Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. Learn more on MITRE.

Inclusion of Functionality from Untrusted Control Sphere

The product imports, requires, or includes executable functionality (such as a library) from a source that is outside of the intended control sphere. Learn more on MITRE.

Credits